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Cyc

Cyc. Jaehui Park Summarized by Jaehui Park , IDS Lab., Seoul National University Presented by Jaehui Park , IDS Lab., Seoul National University. CycL. Declarative language Syntax derives from first-order predicate calculus Lisp CycL expressions consist of Terms

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Cyc

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  1. Cyc Jaehui Park Summarized by Jaehui Park, IDS Lab., Seoul National University Presented by Jaehui Park, IDS Lab., Seoul National University

  2. CycL • Declarative language • Syntax derives from • first-order predicate calculus • Lisp • CycL expressions • consist of Terms • Constants, non-atomic terms, variables • It goes far beyond first order logic • In order to express common sense

  3. Constants • The concept names in Cyc • Vocabulary words in Cyc knowledge base • Starting with “#$” • Individuals • #$ BillJ, #$MapleTree #$France • Collections • #$Tree-ThePlant (instance of the collection) • Truth Functions • Being applied to one or more concepts and return true or false • Connectives • #$and ,#$or, #$not, #$implies • Quantifiers • #$forAll, #$thereExists • Functions • Producing new terms from given ones • #$FruitFn (a type of plants -> return the collection of its fruits)

  4. Connectives & Quantification • Logical Connectives • #$not, #$and, #$or • #$implies • Returns true iff it is not the case that its first argument is true and its second argument is false • E.g. • (#$implies (#$owns #$Fred #$Bike001) (#$colorOfObject #$Bike001 #$RedColor)) • Quantification • #$forAll, #$thereExists, #$thereExistExactly, #$thereExistAtLeast, #$thereExistAtMost • E.g. • (#$implies (#$isa ?A #$Animal) (#$thereExists ?M (#$mother ?A ?M)))

  5. Variables • Constants whose identities are not specified • Starting with “?” • E.g. (?FOO) • E.g. (#$colorOfObject ?CAR ?COLOR) • CycFormula • A formula is an expression in a formal language that makes some declarative statement about the world. • Well-formed formulas are called CycFormular • E.g. • (#$likesAsFriend #$DougLenat #$KeithGoolsbey)

  6. Specialization & Generalization • Predicates • #$isa • Specialization • Describing the one item is an instance of some collection • #$genls • Generalization • Describing the one collection is a subcollection of another one • Examples • (#$isa #$GeorgeBush #$UnitedStatesPresident) \; • George Bush belongs to the collection of U.S. presidents • (#$genls #$Tree-ThePlant #$Plant) \; • All trees are plants • (#$capitalCity #$France #$Paris) \; • Paris is the capital of France

  7. Rules • Sentence containing variables • Starting with “?” • Example • (#$implies (#$and (#$isa ?OBJ ?SUBSET) (#$genls ?SUBSET ?SUPERSET)) (#$isa ?OBJ ?SUPERSET)) • If OBJ is an instance of the collection SUBSET and SUBSET is a subcollection of SUPERSET, then OBJ is an instance of the collection SUPERSET.

  8. Assertions • CYC knowledge base • A large number of assertions • A formula • CycFormlas • A microtheory • Cyc constant denoting assertions which are grouped together because they share a set of assumptions • #$Microtheroy • A truth value • :#$isa , #$genls • A direction • Hierarchy of “when it gets used” • A support • Consists of one or more justifications which form the support the presence of the assertion in the KB.

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