Common Logic

Common Logic (CL) is a framework for a family of logic languages, based on first-order logic, intended to facilitate the exchange and transmission of knowledge in computer-based systems.[1]

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 interpretation. Each dialect may be then treated as a formal language. 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 mechanically 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".[2] It is available for purchase from ISO's catalog, and is freely available from ISO's index of publicly available standards.[3]

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-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 OWL 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.


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

See also


  1. ^ Sowa, John F. "Conceptual graphs summary." Conceptual Structures: current research and practice 3 (1992): 66.
  2. ^ International Organization for Standardization (ISO)
  3. ^ Common Logic Standard First Edition
Acct (protocol)

The acct URI scheme is a proposed internet standard published by the Internet Engineering Task Force, defined by RFC 7565. The purpose of the scheme is to identify, rather than interact, with user accounts hosted by a service provider. This scheme differs from the DNS name which specifies the service provider.The acct URI was intended to be the single URI scheme that would return information about a person (or possibly a thing) that holds an account at a given domain.

Conceptual graph

A conceptual graph (CG) is a formalism for knowledge representation. In the first published paper on CGs, John F. Sowa (Sowa 1976) used them to represent the conceptual schemas used in database systems. The first book on CGs (Sowa 1984) applied them to a wide range of topics in artificial intelligence, computer science, and cognitive science.

Controlled natural language

Controlled natural languages (CNLs) are subsets of natural languages that are obtained by restricting the grammar and vocabulary in order to reduce or eliminate ambiguity and complexity. Traditionally, controlled languages fall into two major types: those that improve readability for human readers (e.g. non-native speakers),

and those that enable reliable automatic semantic analysis of the language.

The first type of languages (often called "simplified" or "technical" languages), for example ASD Simplified Technical English, Caterpillar Technical English, IBM's Easy English, are used in the industry to increase the quality of technical documentation, and possibly simplify the (semi-)automatic translation of the documentation.

These languages restrict the writer by general rules such as "Keep sentences short", "Avoid the use of pronouns", "Only use dictionary-approved words", and "Use only the active voice".The second type of languages have a formal logical basis, i.e. they have a formal syntax and semantics, and can be mapped to an existing formal language, such as first-order logic. Thus, those languages can be used as knowledge representation languages, and writing of those languages is supported by fully automatic consistency and redundancy checks, query answering, etc.

Diagrammatic reasoning

Diagrammatic reasoning is reasoning by means of visual representations. The study of diagrammatic reasoning is about the understanding of concepts and ideas, visualized with the use of diagrams and imagery instead of by linguistic or algebraic means.

Ekman transport

Ekman transport, part of Ekman motion theory first investigated in 1902 by Vagn Walfrid Ekman, refers to the wind-driven net transport of the surface layer of a fluid that, due to the Coriolis effect, occurs at 90° to the direction of the surface wind. This phenomenon was first noted by Fridtjof Nansen, who recorded that ice transport appeared to occur at an angle to the wind direction during his Arctic expedition during the 1890s. The direction of transport is dependent on the hemisphere: in the northern hemisphere, transport occurs at 90° clockwise from wind direction, while in the southern hemisphere it occurs at a 90° counterclockwise.

Front controller

The front controller software design pattern is listed in several pattern catalogs and related to the design of web applications. It is "a controller that handles all requests for a website", which is a useful structure for web application developers to achieve the flexibility and reuse without code redundancy.

Gate array

A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops,etc.) according to a custom order by adding metal interconnect layers in the factory.

Similar technologies have also been employed to design and manufacture analog, analog-digital, and structured arrays, but, in general, these are not called gate arrays.

Gate arrays have also been known as Uncommitted Logic Arrays (ULAs) and semi-custom chips.

Internationalized Resource Identifier

The Internationalized Resource Identifier (IRI) – is an internet protocol standard which extends the ASCII characters subset of the Uniform Resource Identifier (URI) protocol. It was defined by the Internet Engineering Task Force (IETF) in 2005 as a new internet standard to extend the existing URI scheme. The primary standard is defined by the RFC 3987. While URIs are limited to a subset of the ASCII character set, IRIs may contain characters from the Universal Character Set (Unicode/ISO 10646), including Chinese or Japanese kanji, Korean, Cyrillic characters, and so forth.

Knowledge Interchange Format

Knowledge Interchange Format (KIF) is a computer language designed to enable systems to share and re-use information from knowledge-based systems. KIF is similar to frame languages such as KL-One and LOOM but unlike such language its primary role is not intended as a framework for the expression or use of knowledge but rather for the interchange of knowledge between systems. The designers of KIF likened it to PostScript. PostScript was not designed primarily as a language to store and manipulate documents but rather as an interchange format for systems and devices to share documents. In the same way KIF is meant to facilitate sharing of knowledge across different systems that use different languages, formalisms, platforms, etc.

KIF has a declarative semantics. It is meant to describe facts about the world rather than processes or procedures. Knowledge can be described as objects, functions, relations, and rules. It is a formal language, i.e., it can express arbitrary statements in first order logic and can support reasoners that can prove the consistency of a set of KIF statements. KIF also supports non-monotonic reasoning. KIF was created by Michael Genesereth, Richard Fikes and others participating in the DARPA knowledge Sharing Effort.Although the original KIF group intended to submit to a formal standards body, that did not occur. A later version called Common Logic has since been developed for submission to ISO and has been approved and published. A variant called SUO-KIF is the language in which the Suggested Upper Merged Ontology is written.

Like a Velvet Glove Cast in Iron

Like a Velvet Glove Cast in Iron is a graphic novel by American cartoonist Daniel Clowes. The book follows a rather fantastic and paranoid plot, very different from the stark realism of Clowes' later more widely known Ghost World. It contains nightmarish imagery, including dismemberment, deformed people and animals, and sexual fetishism.

Clowes has talked about how the story was inspired by his dreams, as well as a recurring dream of his ex-wife's:

A lot of it is just daydreams, where ... I can just have these thoughts that are uncontrolled by common logic, and then I start to see things in a different way. It's sort of the same thing as when you wake up from a long dream and you, for one minute, see the absurdity of the world.

The book's title is a quote from the Russ Meyer film Faster, Pussycat! Kill! Kill! (The full line, as delivered by Lori Williams, is "You're cute, like a velvet glove cast in iron. And like a gas chamber, Varla, a real fun gal.")

List of constructed languages

The following list of notable constructed languages is divided into auxiliary, ritual, engineered, and artistic (including fictional) languages, and their respective subgenres. All entries on this list have further information on separate Wikipedia articles.

Ontology Definition MetaModel

The Ontology Definition MetaModel (ODM) is an Object Management Group (OMG) specification to make the concepts of Model-Driven Architecture applicable to the engineering of ontologies. Hence, it links Common Logic (CL), the Web Ontology Language (OWL), and the Resource Description Framework (RDF).

OWL and RDF were initially defined to provide an XML-based machine to machine interchange of metadata and semantics. ODM now integrates these into visual modeling, giving a standard well-defined process for modeling the ontology, as well as, allowing for interoperability with other modeling based on languages like UML, SysML and UPDM.

Ontology language

In computer science and artificial intelligence, ontology languages are formal languages used to construct ontologies. They allow the encoding of knowledge about specific domains and often include reasoning rules that support the processing of that knowledge. Ontology languages are usually declarative languages, are almost always generalizations of frame languages, and are commonly based on either first-order logic or on description logic.

Process Specification Language

The Process Specification Language (PSL) is a set of logic terms used to describe processes. The logic terms are specified in an ontology that provides a formal description of the components and their relationships that make up a process. The ontology was developed at the National Institute of Standards and Technology (NIST), and has been approved as an international standard in the document ISO 18629.

The Process Specification Language can be used for the representation of manufacturing, engineering and business processes, including production scheduling, process planning, workflow management, business process reengineering, simulation, process realization, process modelling, and project management. In the manufacturing domain, PSL's objective is to serve as a common representation for integrating several process-related applications throughout the manufacturing process life cycle.

RuleML Symposium

The annual International Web Rule Symposium (RuleML) is an international academic conferences on research, applications, languages and standards for rule technologies. Since 2017 it is organised as International Joint Conference on Rules and Reasoning (RuleML+RR). It is a conference in the field of rule-based programming and rule-based systems including production rules systems, logic programming rule engines, and business rules engines/business rules management systems; Semantic Web rule languages and rule standards (e.g., RuleML, LegalRuleML, Reaction RuleML, SWRL, RIF, Common Logic, PRR, Decision Model and Notation (DMN), SBVR); rule-based event processing languages (EPLs) and technologies; and research on inference rules, constraint handling rules, transformation rules, decision rules, production rules, and ECA rules. RuleML+RR is the leading conference to build bridges between academia and industry in the field of Web rules and its applications, especially as part of the semantic technology stack. RuleML+RR is commonly listed together with other Artificial Intelligence conferences worldwide.

Semantics of Business Vocabulary and Business Rules

The Semantics of Business Vocabulary and Business Rules (SBVR) is an adopted standard of the Object Management Group (OMG) intended to be the basis for formal and detailed natural language declarative description of a complex entity, such as a business. SBVR is intended to formalize complex compliance rules, such as operational rules for an enterprise, security policy, standard compliance, or regulatory compliance rules. Such formal vocabularies and rules can be interpreted and used by computer systems. SBVR is an integral part of the OMG's model-driven architecture (MDA).


XCL is a three-letter abbreviation with multiple meanings, as described below:

Xlib Compatibility Layer

Cluff Lake Airport, the IATA airport code

Classical Armenian, the ISO 639-3 code being xcl.

eXtensible Characterisation Language developed at the University of Cologne

the XML interchange format for Common logic

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