2005 FirstOrderizedResearchcycExpres
- (Ramachandran et al., 2005) ⇒ Deepak Ramachandran, Pace Reagan, and Keith Goolsbey. (2005). “First-orderized Researchcyc: Expressivity and Efficiency in a Common-sense Ontology.” In: AAAI Workshop on Contexts and Ontologies: Theory, Practice and Applications.
Subject Headings: Common Sense Ontology; Cyc Ontology; ResearchCyc.
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Abstract
Cyc is the largest existing common sense knowledge base. Its ontology makes heavy use of higher-order logic constructs such as a context system, first class predicates, etc. Many of these higher-order constructs are believed to be key to Cyc’s ability to represent common sense knowledge and reason with it efficiently. In this paper, we present a translation of a large part (around 90%) of the Cyc ontology into First-Order Logic. We discuss our methodology, and the tradeoffs between expressivity and efficiency in representation and reasoning. We also present the results of experiments using VAMPIRE, SPASS, and the E Theorem Prover on the first-orderized Cyc KB. Our results indicate that, while the use of higher-order logic is not essential to the representability of common sense knowledge, it greatly improves the efficiency of reasoning.
1. Introduction
ResearchCycTM is a version of Cycorp Inc.’s Cyc Knowledge Base - the world’s largest general common-sense ontology and reasoning engine. ResearchCyc is available under a free license, and consists of 1,074,484 assertions in a language of 122,658 symbols (not including strings or numbers). By contrast, the IEEE Suggested Upper Merged Ontology (Niles & Pease 2001) consists of 60,000 axioms over 20,000 terms.
A significant feature of ResearchCyc’s design is the incorporation of higher-order assertions in its KB. (For the rest of this paper we will use the term ”higher-order” to mean any feature beyond ordinary first-order logic, like a context system or quantification over predicates.) The reasons for this are both philosophical and pragmatic; it is widely believed that a complete specification of what is understood to be “common sense knowledge” requires some kind of higher-order features. For example, Boolos (Boolos 1984) discusses two sentences that cannot be represented in a logic without predicate quantification (non-firstorderizable):
- . Some critics admire only one another.
- . Some of Fianchetto’s men went into the warehouse unaccompanied by anyone else.
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| Author | volume | Date Value | title | type | journal | titleUrl | doi | note | year | |
|---|---|---|---|---|---|---|---|---|---|---|
| 2005 FirstOrderizedResearchcycExpres | Deepak Ramachandran Pace Reagan Keith Goolsbey | First-orderized Researchcyc: Expressivity and Efficiency in a Common-sense Ontology |