copyright © 2002 cycorp writing efficient cycl part 1 part one –simpler is better –use rule...

Copyright © 2002 Cycorp

Writing Efficient CycL Writing Efficient CycL Part 1Part 1

• Part One– Simpler is Better

– Use Rule Macro Predicates

– Create Simplifying Vocabulary

• Part Two– Factor out Commonality

– Existence is Expensive

– Exceptions are Exceptional

– State Negations Explicitly

– Generalize -- Don’t List– Use #$different



• Simpler is Better• Use Rule Macro Predicates• Create Simplifying Vocabulary


Simpler is BetterSimpler is Better

• Modularity leads to generality and reuse

• If it looks too complicated, it is

BETTER WORSE

GAFsBinary

Horn rulesSmall rules

RulesNon-binary

Non-horn rules1 gargantuan rule


GAFs are better than rulesGAFs are better than rules

BETTER WORSE

GAFsBinary


RulesNon-binary


Example: #$hasDiet

(#$hasDiet #$koala #$eucalyptus)(#$hasDiet #$cow #$grass)(#$hasDiet #$vampireBats #$blood)(#$hasDiet #$venusFlytrap #$fly-Insect)

Rule Macro Predicates = Rules + GAFs

99.9% of KB should be GAFs


Binary is better than non-binaryBinary is better than non-binary

BETTER WORSE

GAFsBinary


RulesNon-binary


Avoid gratuitously ternary or quaternary predicates:

(graduationDate ?PRSN ?DGREETYP ?DATE)

(graduationEvent ?PRSN ?EVENT)(dateOfEvent ?EVENT ?DATE)(degreeTypeOfGraduationEvent ?EVENT ?DGREETYP)

Value Null Vaule Vaule Vaule Null VauleNull Vaule Vaule Vaule Null Vaule Vaule

Non-Normal Table

Normal Table


Horn-rules are better than Horn-rules are better than non-horn rulesnon-horn rules

BETTER WORSE

GAFsBinary


RulesNon-binary


Horn Rule: (#$implies (#$isa ?ANIMAL #$Bird) (#$thereExists ?WING (#$and (#$isa ?WING #$Wing-AnimalBodyPart)

(#$anatomicalParts ?ANIMAL #$Wing-AnimalBodyPart)))))

Consequent of Non-horn Rule: (#$or (#$objectHasColor #$Rover #$TanColor) (#$objectHasColor #$Rover #$BlackColor))

If all of this is true, then


Several small rules are better Several small rules are better than one gargantuan rulethan one gargantuan rule

BETTER WORSE

GAFsBinary


RulesNon-binary


1 Gargantuan Rule:– way too complex to be correct– will never get used – large memory requirement– likely does not say what was intended– cannot be generalized


Simpler is betterSimpler is better(#$genlPreds #$brothers #$siblings)

is better than

(#$implies (#$brothers ?AGT ?BRO) (#$siblings ?AGT ?BRO))

genlPredsRule Macro Predicates

helper functionmacros

ProgrammingOE


Reason with the vocabulary itselfReason with the vocabulary itselfInstead of this:

(eats Cheetah Wildebeest)

(implies

(and

(isa ?EAT Eating)

(isa ?CH1 Cheetah)

(isa ?WIL1 Wildebeest)

(doer ?EAT ?CH1)

(objectActedOn ?WIL1)

(hasAttributes ?WIL1 Deceased))

(eats Cheetah Antelope)

(implies

(and

(isa ?EAT Eating)

(isa ?CH1 Cheetah) . . .

Do this:

(animalTypeEatsAnimalType Cheetah Wildebeest)

(implies (animalTypeEatsAnimalType ?ANM1 ?ANM2) (hasAttributes ?ANM2 Deceased))

(animalTypeEatsAnimalType Cheetah Antelope)

One rule applies to all animal types


Reason with the vocabulary itself Reason with the vocabulary itself (cont.)(cont.)

Entering a lot of rich knowledge in a new

domain?

• add some abstractions as new vocabulary

• define new vocabulary in ways that link it up to other existing vocabulary

Now you can tersely write the things you need to say.


Add Rule Macro PredicatesAdd Rule Macro Predicates

Simple vocabulary for the sake of being simple is not worth it. Add Rule Macro Predicates.

An extreme example of operating with too little vocabulary:

0(#$SuccessorFn 0)(#$SuccessorFn (#$SuccessorFn 0))(#$SuccessorFn (#$SuccessorFn (#$SuccessorFn 0)))(#$SuccessorFn (#$SuccessorFn (#$SuccessorFn (#$SuccessorFn 0)))). . .


Some False IdeasSome False Ideas

Erroneous Mindset“vocabulary is expensive”

“complex assertions are cheap”

– Physics Envy– Maxwell’s Equations of KR


New Vocabulary Will Not Make New Vocabulary Will Not Make Rules Less ReusableRules Less Reusable

• The same kinds of tools that help you find #$Dog will help you find your new vocabulary

• The meaning of #$Dog is only defined by how it’s linked up to other things in the system -- all new vocabulary must be linked up properly

• All truly large-scale, reusable, interesting knowledge bases are going to be big

• For all large-scale knowledge bases, you must have tools


OE vs KE vs SME’s and Their OE vs KE vs SME’s and Their VocabularyVocabulary

• OE: make it so that a KE can create vocabulary

• KE: understand enough about the logic so that they can create vocabulary

• SME: use the vocabulary

– Should be able to say everything that they need to say with the available vocabulary


The Rule of 10The Rule of 10

Simplifying many assertions is reason enough to create new vocabulary

(#$isa ?MAL #$MalePerson)

is better than(#$and (#$isa ?MAL #$Person) (#$hasGender ?MAL #$Masculine))


Why Simplify Vocabulary?Why Simplify Vocabulary?

• Cyc is not a frame system:– Adding new vocabulary is NOT expensive

– Creating collections is NOT expensive

– Creating predicates is NOT expensive

– Creating functions is NOT expensive

– Creating microtheories is NOT expensive

• Reasoning with overly complicated rules is expensive

• Reasoning with overused vocabulary is hard to focus


Summary SlideSummary Slide

• Simpler is Better

• Use Rule Macro Predicates

• Create Simplifying Vocabulary

copyright © 2002 cycorp writing efficient cycl part 1 part one –simpler is better –use rule...

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