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The project was started in 1984 by Doug Lenat. The name "Cyc" (from "encyclopedia", pronounced like psych) is a registered trademark owned by Cycorp, Inc. in Austin, Texas, a company run by Lenat and devoted to the development of Cyc. The original project is proprietary, but a smaller version of the database has been released as OpenCyc under an open source license.

Typical pieces of knowledge represented in the database are "Every tree is a plant" and "Plants die eventually". When asked whether trees die, the inference engine can draw the obvious conclusion and answers the question correctly. The Knowledge Base (KB) contains over a million human-defined assertions, rules or common sense ideas. These are formulated in the language CycL, which is based on predicate calculus and has a syntax similar to the Lisp programming language. CycL users pun that they are "cyclists".

Much of the current work on the Cyc project continues to be knowledge engineering, representing facts about the world by hand, and implementing efficient inference mechanisms on that knowledge. Increasingly, however, the thrust of work at Cycorp involves giving the Cyc system the ability to communicate with end users in natural language, and to assist with the knowledge formation process.

1 Description of the database, terminology

The concept names in Cyc are known as constants. Constants start with "#$" and are case-sensitive. There are constants for:

• Individual items known as individuals, such as #$BillClinton or #$France.
• Collections, such as #$Tree-ThePlant (containing all trees) or #$EquivalenceRelation (containing all equivalence relations). A member of a collection is called an instance of that collection.
• Truth Functions which can be applied to one or more other concepts and return either true or false. For example #$siblings is the sibling relationship, true if the two arguments are siblings. By convention, truth function constants start with a lower-case letter. Truth functions may be broken down into logical connectives (such as #$and, #$or, #$not, #$implies), quantifiers (#$forAll, #$thereExists, etc.) and predicates.
• Functions, which produce new terms from given ones. For example, #$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".

The most important predicates are #$isa and #$genls. The first one describes that one item is an instance of some collection, the second one that one collection is a subcollection of another one. Facts about concepts are asserted using certain CycL sentences. Predicates are written before their arguments, in parentheses:

"Bill Clinton belongs to the collection of U.S. presidents" and

"All trees are plants".

"Paris is the capital of France."

Sentences can also contain variables, strings starting with "?". One important rule asserted about the #$isa predicate reads

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". Another typical example is

which means that for every instance of the collection #$ChordataPhylum (i.e. for every chordate), there exists a female animal (instance of #$FemaleAnimal) which is its mother (described by the predicate #$biologicalMother).

The knowledge base is divided into microtheories (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 #$MathMt, the microtheory containing mathematical knowledge. The microtheories can inherit from each other and are organized in a hierarchy: one specialization of #$MathMt is #$GeometryGMt, the microtheory about geometry.

2 OpenCyc

The first version of OpenCyc was released in May 20012001 is a common year starting on Monday (see link for calendar), and also: The International Year of the Volunteer The United Nations Year of Dialogue Among Civilizations Events January January 1 A black monolith measuring approximately nine feet tall ap. The knowledge base contains about 6,000 concepts and 60,000 facts, has been combined with WordNetWordNet is a semantic lexicon for the English language. It groups English words into sets of synonyms called synsets provides short definitions, and records the various semantic relations between these synonym sets. The purpose is twofold: to produce a co, is released under LGPL, and can be browsed online. The program which allows you to browse and edit the database as well as to draw inferences is released for free, but only as a binary, without source code. That is, it is freeware, but not free software ( open source). It runs on GNU/ LinuxThis article is about Linux-based operating systems, GNU/Linux, and related topics. See Linux kernel for the kernel itself. See Linux (washing powder) for the Swiss brand of washing powder. Tux, a plump penguin, is the official Linux mascot Linux is the n and WindowsImage use policy. Microsoft Windows is a range of commercial operating environments for personal computers. The range was first introduced by Microsoft in 1985 and eventually has come to dominate the world personal computer market. All recent versions of.

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CyclingCycling is a recreation, a sport, and a means of transport across land. It involves riding bicycles, unicycles, tricycles, and other human powered vehicles (HPVs). As a sport it is governed internationally by the Union Cycliste Internationale in Switzerla CycladesAegean sea from the island of Santorini The Cyclades from the Greek , ("circular," modern Greek Kikladhes is the name of an island group south-east of the mainland of Greece. It is a part of the vast number of islands which constitute the Greek archipelag CycCyc is an artificial intelligence project which attempts to assemble a comprehensive ontology and database of everyday common-sense knowledge, with the goal of enabling AI applications to perform human-like reasoning. The project was started in 1984 by Do Cyclic adenosine monophosphateCyclic adenosine monophosphate cAMP cyclic AMP or 3'-5'-cyclic adenosine monophosphate) is a molecule that is important in many biological processes; it is derived from adenosine triphosphate (ATP). cAMP is a second messenger, used for intracellular signa Cyclotrimethylene trinitramineCyclotrimethylene trinitramine also known as RDX cyclonite or hexogen is an explosive material widely used by the military. There are many interpretations of its acronym including (but not limited to) Royal Demolition eXplosive and Research Department Exp Cyclone programming languageThe Cyclone programming language is intended to be a safe dialect of the C programming language. It is designed to avoid the buffer overflow and other vulnerabilities that are inherent in C, without losing the power and convenience of C as a tool for syst Cyclops (disambiguation) Cyclic redundancy check Cycloid Cyclone Cyclotron Cyclothymia Cyclic group Cyclops Cyclopentadiene