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  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Algebraic data structures for topological summaries

    Ezra Miller

    Duke University, Department of Mathematics

    and Department of Statistical Science

    [email protected]

    ongoing mathematics with Justin Curry (Duke postdoc)

    Ashleigh Thomas (Duke grad)

    Surabhi Beriwal (Duke undergrad)

    and biology with David Houle (Florida State, Biology)

    Mathematical Congress of the Americas

    Montréal, Quebeca, Canada

    27 July 2017

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Outline

    1. Fly wings

    2. Biological background

    3. Persistent homology

    4. Poset modules

    5. Encoding

    6. Fringe presentation

    7. Decomposition

    8. Future directions

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fruit fly wings

    Normal fly wings [images from David Houle’s lab]:

    1

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fruit fly wings

    Normal fly wings [images from David Houle’s lab]:

    Topologically abnormal veins:

    1

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fruit fly wings

    photographic image

    2

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fruit fly wings

    spline

    2

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Biological background

    What generates topological novelty?[Houle, et al.]: selecting for certain continuous wing vein deformations yields

    • skew toward more oddly shaped wings, but also• much higher rate of topological novelty

    Hypothesis. Topological novelty arises when directional selection pushescontinuous variation in a developmental program beyond a certain threshold.

    Test the hypothesis• "plot" wings in "form space"• determine whether topological variants lie "in the direction of" continuous

    shape selected for, and at the extreme in that direction

    Goal. Statistical analysis encompassing topological vein variation, givingappropriate weight to new singular points in addition to varying shape

    • compare phenotypic distance to genotypic distance; needs• metric specifying distance between topologically distinct wings

    To proceed. Statistics with fly wings as data objects statistics withmultiparameter persistence diagrams as data objects

    Need. Data structures, algorithms, theoretical guarantees3

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Example: filling brains [w/Bendich, Marron, Pieloch, Skwerer]

    5

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Persistent homology

    Topological space X• Fixed X homology HiX for each dimension i

    • Build X step by step: measure evolving topology

    Def. Let X•

    be a filtered space, meaning ∅ = X0 ⊂ X1 ⊂ · · · ⊂ Xm = X .The persistent homology HiX• is HiX1 → HiX2 → · · · → HiXm, a sequence ofvector space homomorphisms.

    Examples

    1. Given a function f : X → R, let Xt = f−1

    ((−∞, t ]

    ). Choose t0, . . . , tm ∈ R

    so HiXt changes from tk to tk+1

    2. Any simplicial complex: build it simplex by simplex in some order

    History. invented by [Frosini, Landi 1999], [Robins 1999];[Edelsbrunner, Letscher, Zomorodian 2002]: includes efficient computation;

    [Carlsson, Zomorodian 2009]: multiparameter persistence;

    [Cagliari, Harer, Knudson, Mukherjee,. . . ]: developments in theory, applications

    4’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set

    • 2nd parameter: distance from edge set

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set given as points in R2

    • 2nd parameter: distance from edge set given as Bézier curves

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Multiparameter persistence

    Plan. (with Houle, Curry, Thomas, +. . . ) Encode with 2-parameter persistence

    • 1st parameter: distance from vertex set (require distance ≥ −r )

    • 2nd parameter: distance from edge set (require distance ≤ s)

    Sublevel set Wr ,s is near edges but far from vertices

    Z2-module:

    ↑ ↑ ↑

    → Hr−ε,s+δ → Hr,s+δ → Hr+ε,s+δ →↑ ↑ ↑

    → Hr−ε,s → Hr,s → Hr+ε,s →↑ ↑ ↑

    → Hr−ε,s−δ → Hr ,s−δ → Hr+ε,s−δ →↑ ↑ ↑

    6

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Examples

    A piece of fly wing vein The (r , s)-plane R2

    Observations

    • stratification alters persistence module

    • discretization approximates algebraic

    7

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Modules over posets

    Filter X by poset Q of subspaces: Xq ⊆ X for q ∈ Q ⇒ persistent homology is a

    Def. Q-module:

    • Q-graded vector space H =⊕

    q∈Q Hq with

    • homomorphism Hq → Hq′ whenever q � q′ in Q such that

    • Hq → Hq′′ equals the composite Hq → Hq′ → Hq′′ whenever q � q′ � q′′

    Examples

    • brain arteries: Q = {0, . . . ,m}

    • brain arteries: Q = R

    • wing veins: Q = Z2

    • wing veins: Q = R2

    • multifiltration Q = Rn n real filtrations of any topological space

    • Q = Zn implies H = Zn-graded k[x1, . . . , xn]-module

    – standard combinatorial commutative algebra

    – some proofs proceed by reducing to this case

    8’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    An R2-module finitely encoded

    10

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    An R2-module finitely encoded

    10

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    An R2-module finitely encoded

    10

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Encoding persistence modules

    Finiteness conditions: • Zn-modules: finitely generated⇔ noetherian• Rn-modules from data analysis↔ ??

    Def. H induces isotypic regions in Q: equivalence classes for equivalencerelation generated by a ∼ b whenever • a � b in Q

    and • Ha∼−→ Hb.

    H is tame if dimk Hq

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u

    • downset D ⊆ Q if D =⋃

    d∈D Q�d

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Examples• In R2:

    U = and = D

    • In R3:

    U =

    semialgebraic

    or

    piecewise linear

    = D

    [Andrei Okounkov, Limit shapes, real and imagined, Bulletin of the AMS 53 (2016), no. 2, 187–216]

    12

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Examples• In R2:

    U = and = D

    • In R3:

    U =

    semialgebraic

    or

    piecewise linear

    = D

    [Andrei Okounkov, Limit shapes, real and imagined, Bulletin of the AMS 53 (2016), no. 2, 187–216]

    12

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u

    • downset D ⊆ Q if D =⋃

    d∈D Q�d

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u

    • downset D ⊆ Q if D =⋃

    d∈D Q�d

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    ϕ11

    has image k

    as long as ϕ11 6= 0.

    12’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    ϕ11

    has image k

    as long as ϕ11 6= 0.

    12’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Fringe presentation

    Def. Fix a poset Q.• upset U ⊆ Q if U =

    u∈U Q�u k[U] ⊆ k[Q]

    • downset D ⊆ Q if D =⋃

    d∈D Q�d k[Q]։ k[D]

    For any subset S ⊆ Q, set k[S] =⊕

    s∈S ks.

    Def [w/Curry & Thomas]. A fringe presentation of H is a monomial matrix

    birth upsets →

    U1...

    Uk

    D1 · · · Dℓϕ11 · · · ϕ1ℓ

    .... . .

    ...

    ϕk1 · · · ϕkℓ

    ← death downsets

    ← scalar entries

    k[U1]⊕ · · · ⊕ k[Uk ] = F −−−−−−−−−−−−−−−−→ E = k[D1]⊕ · · · ⊕ k[Dℓ]

    with image(F → E) ∼= H.

    Compare. [Chachólski, Patriarca, Scolamiero, Vaccarino] “monomial presentation”but fringe presentation is new even for finitely generated Z2-modules

    Thm [w/Curry & Thomas]. finitely encoded⇔ admits fringe presentation

    11’’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Decomposition

    Thm [w/Curry & Thomas]. Finitely encoded Rn-modules admit minimalprimary decomopsition: H =

    faces τ Hτ with socτH−→∼

    socτHτ

    Problem. Encoding, fringe presentation, primary decomposition not canonicalexcept for downsets (compare: Zn-graded modules vs. monomial ideals)

    Solution. Births and deaths are functorial QR code• generators ( = births) of each type and shape• cogenerators ( = socle elements = deaths) of each type and shape

    – type: infinite vs. bounded directions: primary decomposition

    – shape: tangent cone topology of corresponding upset or downset

    • module structure on H ↔ linear map: births→ deaths

    Finiteness / semialgebraic properties / computability from finite encoding

    Goal. Statistics with rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)[Carlsson, Zomorodian 2009]

    Proposal. fringe presentation framework to compute rank functions• data structure (level sets of rank function are semialgebraic)

    • algorithms (semialgebraic geometry, computational commutative algebra)13

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    Thank You14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Future directions

    Algebra• QR codes: module-theoretic topologies on generators and cogenerators

    • Syzygy conj: Rn-modules have indicator-homological dimension ≤ n

    Computation• calculate encoding / fringe presentation from vertices and Bézier curves

    • homological algebra with semialgebraic indicator modules

    • data structures for rank functions; computation for statistics

    Statistics• geometric probability/statistics on stratified spaces

    • No-moduli conj: rank function Rn × Rn → N(a � b) 7→ rank(Ha → Hb)

    determines H0 and Hn−1modules for objects in Rn

    • Local statistical sufficiency conj: Different fly wings yield nonisomorphic

    modules locally; i.e., deformation of fly wing splines⇒ QR code changes

    Topology. Biparameter persistence as persistent intersection homology

    Biology. The topological novelty hypothesis

    Thank You14

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Topology of probability distributions

    Approximation by bandwidth r expansion of size n sample• geometry: sample Sn from space M ⇒ M ≈ Br (S) =

    x∈S Br (x)

    • statistics: sample µn from measure µ⇒ µ ≈ Ur (µn) =1n

    x∈S1

    vol(r)Ur (x)

    Ur (x) = uniform measure on Br (x) and vol(r) = volume of ball of radius rIn general: Ur Kr arbitrary kernel and µn ν arbitrary measure

    Def. µ has density F ⇒ Br (µ) has density Kr ∗ F (x) =∫

    MKr (y − x)dµ(y).

    Def. support at sensitivity s:• ν has density F ⇒ ν≥1/s =

    {x ∈ M | F (x) ≥ 1

    s

    }.

    • expansion of µ to bandwidth r and sensitivity s is Br (µ)≥1/s ⊆ M.

    Note:{

    Br (µ)≥rd/s | r ∈ R≥0 and s ∈ R≥1}⊆ M nested as r and s increase

    Def. µ has i th bipersistent homology H rsi (µ) = Hi(Br (µ)≥rd/s

    ), an invariant of µ

    Conj. If µ is stratified—a mixture of smooth measures supported on the strataof a Whitney stratification—then its bipersistent homology is finitely encoded.

    algebra, geometry, combinatorics of H rs∗ (µ)↔ statistics of µ.

    15

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Topology of probability distributions

    Approximation by bandwidth r expansion of size n sample• geometry: sample Sn from space M ⇒ M ≈ Br (S) =

    x∈S Br (x)

    • statistics: sample µn from measure µ⇒ µ ≈ Ur (µn) =1n

    x∈S1

    vol(r)Ur (x)

    Ur (x) = uniform measure on Br (x) and vol(r) = volume of ball of radius rIn general: Ur Kr arbitrary kernel and µn ν arbitrary measure

    Def. µ has density F ⇒ Br (µ) has density Kr ∗ F (x) =∫

    MKr (y − x)dµ(y).

    Def. support at sensitivity s:• ν has density F ⇒ ν≥1/s =

    {x ∈ M | F (x) ≥ 1

    s

    }.

    • expansion of µ to bandwidth r and sensitivity s is Br (µ)≥1/s ⊆ M.

    Note:{

    Br (µ)≥rd/s | r ∈ R≥0 and s ∈ R≥1}⊆ M nested as r and s increase

    Def. µ has i th bipersistent homology H rsi (µ) = Hi(Br (µ)≥rd/s

    ), an invariant of µ

    Conj. If µ is stratified—a mixture of smooth measures supported on the strataof a Whitney stratification—then its bipersistent homology is finitely encoded.

    algebra, geometry, combinatorics of H rs∗ (µ)↔ statistics of µ.

    15

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Bandwidth r expansion / kernel density estimation

    images taken from Confidence sets for persistence diagrams,by Fasy, Lecci, Rinaldo, Wasserman, Balakrishnan, Singh,

    Annals of Statistics 42 (2014), no. 6, 2301–2339.

    16

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Topology of probability distributions

    Approximation by bandwidth r expansion of size n sample• geometry: sample Sn from space M ⇒ M ≈ Br (S) =

    x∈S Br (x)

    • statistics: sample µn from measure µ⇒ µ ≈ Ur (µn) =1n

    x∈S1

    vol(r)Ur (x)

    Ur (x) = uniform measure on Br (x) and vol(r) = volume of ball of radius rIn general: Ur Kr arbitrary kernel and µn ν arbitrary measure

    Def. µ has density F ⇒ Br (µ) has density Kr ∗ F (x) =∫

    MKr (y − x)dµ(y).

    Def. support at sensitivity s:• ν has density F ⇒ ν≥1/s =

    {x ∈ M | F (x) ≥ 1

    s

    }.

    • expansion of µ to bandwidth r and sensitivity s is Br (µ)≥1/s ⊆ M.

    Note:{

    Br (µ)≥rd/s | r ∈ R≥0 and s ∈ R≥1}⊆ M nested as r and s increase

    Def. µ has i th bipersistent homology H rsi (µ) = Hi(Br (µ)≥rd/s

    ), an invariant of µ

    Conj. If µ is stratified—a mixture of smooth measures supported on the strataof a Whitney stratification—then its bipersistent homology is finitely encoded.

    algebra, geometry, combinatorics of H rs∗ (µ)↔ statistics of µ.

    15’

  • Fly wings Biology Persistence Poset modules Encoding Fringe presentation Decomposition Future

    Topology of probability distributions

    Approximation by bandwidth r expansion of size n sample• geometry: sample Sn from space M ⇒ M ≈ Br (S) =

    x∈S Br (x)

    • statistics: sample µn from measure µ⇒ µ ≈ Ur (µn) =1n

    x∈S1

    vol(r)Ur (x)

    Ur (x) = uniform measure on Br (x) and vol(r) = volume of ball of radius rIn general: Ur Kr arbitrary kernel and µn ν arbitrary measure

    Def. µ has density F ⇒ Br (µ) has density Kr ∗ F (x) =∫

    MKr (y − x)dµ(y).

    Def. support at sensitivity s:• ν has density F ⇒ ν≥1/s =

    {x ∈ M | F (x) ≥ 1

    s

    }.

    • expansion of µ to bandwidth r and sensitivity s is Br (µ)≥1/s ⊆ M.

    Note:{

    Br (µ)≥rd/s | r ∈ R≥0 and s ∈ R≥1}⊆ M nested as r and s increase

    Def. µ