Transcript
Page 1: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Geometry, Topology and all your wildest dreams will come true

Don Sheehy

Page 2: Geometry, Topology, and all of Your Wildest Dreams Will Come True

I do theory.

Computational Geometry(geometric approximation algorithms)

Computational Topology(geometric inference)

Page 3: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Applications

Surface reconstruction

Manifold learning

Topological data analysis

Winning Nobel Peace Prizes

Winning Gold Medals in the Olympics

Finding True Love

Page 4: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Computer Scientists want to know the shape of data.

Clustering

Principal Component Analysis

Convex HullMesh Generation

Surface Reconstruction

Page 5: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Point sets have no shape...so we have to add it ourselves.

Page 6: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Distance functions add shape to data.

dP (x) = minp!P

|x ! p|

P! = d!1

P[0, !]

=!

p!P

ball(p, !)

Page 7: Geometry, Topology, and all of Your Wildest Dreams Will Come True

In Persistent Homology, we look at the changes in the shape over time.

Use a simplicial complex rather than the union of balls.

(Think graphs plus triangles, tetrahedra, etc.)

Page 8: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Previous methods build complexes of size nO(d).

We can do this with complexes of size O(n).

nO(d) O(n)

Page 9: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Previously, we had to stop early.

Page 10: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Topology is not Topography

(But in our case, there are some similarities)

Sublevel sets

Page 11: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Nobel Peace Prize!

Page 12: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Mesh generation

Gold Medals!

Page 13: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Where do we get geometric data?

True Love!

Page 14: Geometry, Topology, and all of Your Wildest Dreams Will Come True

Pittsburgh!

Thanks!


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