CycL

CycL is an Ontology in artificial intelligence that was developed specifically for the knowledge base Cyc. Doug Lenat and Ramanathan V. Guha are the first developer.

The original version of CycL was a frame- based language, from which the current version, however, has removed. It is a declaration language based on first order predicate logic. It contains extensions for modal logic and predicate logic higher level.

CycL is used in the Cyc knowledge base to represent the knowledge stored. The source code, written in CycL, is at the OpenCyc project as open source available to increase the usability to support the Semantic Web.

Basic ideas

CycL is based on some basic ideas:

  • Constants are used to refer to stored in the knowledge database concepts.
  • The constants are summarized in a hierarchy forming specializations and generalizations.
  • General rules are created to support the conclusions of the concepts.
  • The veracity of a CycL - set is context-dependent. The contexts are represented in CycL as micro theories.

Constants

The concept names are referred to in CycL as constants. Constants are prefixed with "# $" and are case- sensitive. There are constants for:

  • Individual: proper names such as # $ # $ Bill Clinton or Hamburg.
  • Collection: quantities such as # $ Tree - ThePlant that contains all trees or # EquivalenceRelation that contains all equality relations. An element of a set is called an instance of the set.
  • Truth Function: Functions that return a truth value. These functions represent relationships between concepts, which may be either true or false. By definition, functions in CycL start with a lowercase letter after the prefix. Such atomic functions can be combined into complex sentences by logical links (such as # $ and, # $ or, # $ not, # $ Implies, etc.), quantifiers (such as # $ forAll, # $ thereExists, etc.) and other predicates.
  • Function: Functions that generate from existing terms, new. For example, # $ FruitFn that as an argument returns the set of all its fruits with a lot of plants. By definition, these functions begin with a capital letter after the prefix and end with the characters Sequence "Fn".

Specializations and generalizations

The most important and most commonly used predicates are # isa and # $ genls. The first ( # $ isa ) states that a specified member is an instance of a also stated amount, while the second ( # $ genls ) states that a set is a subset of another.

Statements about concepts are referred to in CycL as sets. Predicates are written before their arguments and set the whole expression in parentheses.

Examples:

" Bill Clinton belongs to the set of American Presidents. "

" All trees are plants. "

" Paris is the capital of France. "

" The set of all dogs and cats do not contain the set of all common elements. "

Regulate

Sets can also contain variables. Variables begin with the prefix "?". An important rule about the predicate # $ isa is:

( # $ Implies     ( # $ and       ( # $ isa? OBJECT? SUBSET )       ( # $ genls? SUBSET? QUANTITY ) )     ( # $ isa? OBJECT? QUANTITY ) ) meaning " When? OBJECT? SUBSET is an element of the set and? SUBSET is a subset of? QUANTITY is, then OBJECT is? also an element of the set? QUANTITY. "

A more complex example is a rule that makes statements about a group or category instead of a single value:

This statement says that for every element of the set # $ ChordataPhylum a female ( Female # $ Animal ) exists, which is ( # $ biological mother ) his mother or put more simply: Each # $ ChordataPhylum has a mother.

Micro theories

The knowledgebase is organized into so-called micro- theories (Mt), which contain a number of concepts and statements about these concepts. Unlike the knowledge base as a whole micro theories may not contain contradictions.

Each micro theory has a name that is a normal constant. By definition, these names end with the string " Mt". Micro theories can inherit statements from underlying micro theories and so are also organized in a separate hierarchy.

Example:

" The micro theory to geometry is a branch of micro theory to mathematics and knows all statements contained in this. "

Swell

  • Translated from the post with a few modifications:
Douglas Lenat
210920
de