Common Logic (CL) is a framework for a family of

logic language Logic programming is a programming paradigm which is largely based on formal logic. Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. Major logic prog ...

s, based on

first-order logic First-order logic—also known as predicate logic, quantificational logic, and first-order predicate calculus—is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science. First-order logic uses quantifie ...

, intended to facilitate the exchange and transmission of

knowledge Knowledge can be defined as awareness of facts or as practical skills, and may also refer to familiarity with objects or situations. Knowledge of facts, also called propositional knowledge, is often defined as true belief that is distin ...

computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

-based systems. The CL definition permits and encourages the development of a variety of different syntactic forms, called ''dialects''. A dialect may use any desired syntax, but it must be possible to demonstrate precisely how the concrete syntax of a dialect conforms to the abstract CL semantics, which are based on a

model theoretic In mathematical logic, model theory is the study of the relationship between formal theories (a collection of sentences in a formal language expressing statements about a mathematical structure), and their models (those structures in which the st ...

interpretation. Each dialect may be then treated as a

formal language In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of sym ...

. Once syntactic conformance is established, a dialect gets the CL semantics for free, as they are specified relative to the abstract syntax only, and hence are inherited by any conformant dialect. In addition, all CL dialects are equivalent (i.e., can be automatically translated to each other), although some may be more expressive than others. In general, a less expressive subset of CL may be translated to a more expressive version of CL, but the reverse translation is only defined on a subset of the larger language.

The ISO Standard

Common Logic is published by ISO as "ISO/IEC 24707:2007 - Information technology — Common Logic (CL): a framework for a family of logic-based languages". It is available for purchase from ISO's catalog, and is freely available from ISO's index of publicly available standards.Common Logic Standard Second Edition
/ref> The CL Standard includes specifications for three dialects, the Common Logic Interchange Format (CLIF) (Annex A), the Conceptual Graph Interchange Format (CGIF) (Annex B), and an

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

-based notation for Common Logic (XCL) (Annex C). The semantics of these dialects are defined in the Standard by their translation to the abstract syntax and semantics of Common Logic. Many other logic-based languages could also be defined as subsets of CL by means of similar translations; among them are the RDF and

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languages, which have been defined by the W3C. The ISO standard's development began in June 2003 under Working Group 2 (Metadata) of Sub-Committee 32 (Data Interchange) under ISO/IEC JTC1, and was completed in October 2007. A technical corrigendum, correcting some errors in the original standard, is being prepared at the time being.

Implementations

COLORE
is a repository of Common Logic Ontologies
Hets
supports Common Logic
cltools
is a PROLOG library with partial support for Common Logic

References

{{DEFAULTSORT:Common Logic Knowledge representation languages ISO standards

The ISO Standard

Implementations

See also

References