361:(Mt), collections of concepts and facts typically pertaining to one particular realm of knowledge. Unlike the knowledge base as a whole, each microtheory is required to be free from contradictions. Each microtheory has a name which is a regular constant; microtheory constants contain the string "Mt" by convention. An example is #$ MathMt, the microtheory containing mathematical knowledge. The microtheories can inherit from each other and are organized in a hierarchy:
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which can be applied to one or more other concepts and return either true or false. For example, #$ siblings is the sibling relationship, true if the two arguments are siblings. By convention, truth function constants start with a lower-case letter. Truth functions may be broken down into logical
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The most important predicates are #$ isa and #$ genls. The first one (#$ isa) describes that one item is an instance of some collection (i.e., specialization), the second one (#$ genls) that one collection is a subcollection of another one (i.e., generalization). Facts about concepts are asserted
278:, which produce new terms from given ones. For example, #$ FruitFn, when provided with an argument describing a type (or collection) of plants, will return the collection of its fruits. By convention, function constants start with an upper-case letter and end with the string "Fn".
349:(Or in looser English, if a given animal has a backbone, then there will be a link from that animal expressing the concept of that animal's "biological Mother". The thing that "fills in the blank" for the biological Mother must also be able to be categorized as a Female Animal.)
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with the interpretation "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".
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Another more complicated example is one that expresses a rule about a group or category rather than any particular individual, is:
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Sentences can also contain variables, strings starting with "?". One important rule asserted about the #$ isa predicate reads
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connectives (such as #$ and, #$ or, #$ not, #$ implies), quantifiers (#$ forAll, #$ thereExists, etc.) and predicates.
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The truth or falsity of a CycL sentence is context-relative; these contexts are represented in CycL as
Microtheories.
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330:(#$ implies (#$ and (#$ isa ?OBJ ?SUBSET) (#$ genls ?SUBSET ?SUPERSET)) (#$ isa ?OBJ ?SUPERSET))
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Grouping the constants together in a generalization—specialization hierarchy, usually called categorization.
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was instrumental in designing early versions of the language. A close CycL variant exists named
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which means that for every instance of the collection #$ ChordataPhylum (i.e., for every
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CycL is used to represent the knowledge stored in the Cyc
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one specialization of #$ MathMt is #$ GeometryGMt, the microtheory about geometry.
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Naming the constants used to refer to information for represented concepts.
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303:"Bill Clinton belongs to the collection of U.S. presidents" and
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List of constructed languages#Knowledge representation
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299:(#$ isa #$ BillClinton #$ UnitedStatesPresident) \;
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437:(January 1991). "Cyc: A Mid-Term Report".
261:). A member of a collection is called an
113:Learn how and when to remove this message
16:For artificial intelligence project, see
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307:(#$ genls #$ Tree-ThePlant #$ Plant) \;
315:(#$ capitalCity #$ France #$ Paris) \;
251:, such as #$ BillClinton or #$ France.
239:The concept names in Cyc are known as
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51:adding citations to reliable sources
357:The knowledge base is divided into
223:Stating general rules that support
162:The original version of CycL was a
803:Knowledge representation languages
319:"Paris is the capital of France."
193:written in CycL released with the
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813:Declarative programming languages
283:Specialization and generalization
213:The basic ideas of CycL include:
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406:Applied Artificial Intelligence
149:artificial intelligence project
38:needs additional citations for
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199:free and open-source software
729:Constraint logic programming
645:Knowledge Interchange Format
602:Procedural reasoning systems
559:Expert systems for mortgages
554:Connectionist expert systems
808:Logic programming languages
625:Attempto Controlled English
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247:Individual items known as
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772:Preference-based planning
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418:10.1080/08839519108927917
481:Knowledge representation
311:"All trees are plants".
716:Constraint satisfaction
134:artificial intelligence
767:Partial-order planning
724:Constraint programming
439:AI Magazine, Fall 1990
197:system is licensed as
174:, with extensions for
650:Web Ontology Language
592:Deductive classifiers
531:Knowledge engineering
516:Model-based reasoning
506:Commonsense reasoning
259:equivalence relations
782:State space planning
762:Multi-agent planning
564:Legal expert systems
501:Case-based reasoning
168:declarative language
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288:using certain CycL
265:of that collection.
227:about the concepts.
170:based on classical
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617:Ontology languages
587:Constraint solvers
180:higher-order logic
153:Ramanathan V. Guha
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36:This article
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607:Rule engines
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412:(1): 45–86.
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103:January 2021
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45:Please help
40:verification
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739:SMT solvers
445:(3): 32–59.
255:Collections
249:individuals
209:Basic ideas
191:source code
176:modal logic
797:Categories
431:Guha, R.V.
394:Guha, R.V.
380:References
73:newspapers
485:reasoning
290:sentences
276:Functions
241:constants
235:Constants
225:inference
368:See also
344:chordate
263:instance
140:used by
136:, is an
691:Prover9
686:Paradox
635:F-logic
195:OpenCyc
87:scholar
666:CARINE
189:. The
187:Cycorp
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62:"CycL"
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696:SPASS
681:Otter
676:Nqthm
640:FO(.)
549:CLIPS
402:"Cyc"
323:Rules
94:JSTOR
80:books
630:CycL
483:and
157:MELD
132:and
126:CycL
66:news
701:TPS
414:doi
146:Cyc
144:'s
128:in
49:by
18:Cyc
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