Cyc Microtheory

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A Cyc Microtheory is an assertion that is used to divide the cyc knowledge base into many domain-specific or distinct reasoning contexts.



References

2017a

  • (Wikipedia, 2017) ⇒ https://en.wikipedia.org/wiki/Cyc Retrieved:2017-6-11.
    • Cyc ( /ˈsk/) is an artificial intelligence project that attempts to assemble a comprehensive ontology and knowledge base of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning.

      The project was started in 1984 by Douglas Lenat at MCC and is developed by the Cycorp company.

      Parts of the project are released as OpenCyc, which provides an API, RDF endpoint, and data dump under an open source license.

      (...) 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.

2017b

  • (Wikipedia, 2017) ⇒ https://en.wikipedia.org/wiki/Upper_ontology#Cyc Retrieved:2017-6-11.
    • A well-known and quite comprehensive ontology available today is Cyc, a proprietary system under development since 1986, consisting of a foundation ontology and several domain-specific ontologies (called microtheories). A subset of that ontology has been released for free under the name OpenCyc, and a more or less unabridged version is made available for free non-commercial use under the name ResearchCyc.

2007

  • (Taylor et al., 2007) ⇒ Taylor, M. E., Matuszek, C., Klimt, B., & Witbrock, M. J. (2007, May). Autonomous Classification of Knowledge into an Ontology. In FLAIRS Conference (pp. 140-145).
    • The Cyc knowledge base (KB) is made up of assertions, formally represented facts of varying levels of complexity (Matuszek et al., 2006), which are asserted into a hierarchy of distinct reasoning contexts called microtheories (or Mts). Microtheories serve several purposes. The primary purpose is to allow each assertion to be correctly contextualized along several dimensions, such as temporal qualification or domain of discussion. From an engineering perspective, making assertions in microtheories allows the background assumptions that apply to a particular domain to be stated only once, and makes it far easier to construct a logically consistent knowledge base.

       Microtheories in Cyc are arranged hierarchically. Very high-level microtheories capture information about broad distinctions such as physical, temporal, and fictional reasoning, and are then subdivided into progressively more specific contexts. An assertion placed into a microtheory must be true in the upward closure of that microtheory (i.e., that microtheory and more general microtheories that subsume it). Cyc currently contains about 4.6 million assertions in 23,627 microtheories, which have an average of approximately three microtheories directly below them in the hierarchy. (...)

      In order to make our experiments tractable, we have chosen one particular sub-area of the Cyc microtheory hierarchy — specifically, the sub-tree rooted under the CyclistsMt microtheory. The CyclistsMt microtheory contains information about Cyc itself and the people who work there, colloquially known as ‘Cyclists’. It is reasonably well-populated with a good cross-section of available terms and predicates, making it a good target for our experiments. This microtheory contains 252 submicrotheories, containing a total of 145,706 assertions.