Semantic reasoner

"Reasoner" redirects here. For other uses, see Reasoner (disambiguation).

A semantic reasoner, reasoning engine, rules engine, or simply a reasoner, is a piece of software able to infer logical consequences from a set of asserted facts or axioms. The notion of a semantic reasoner generalizes that of an inference engine, by providing a richer set of mechanisms to work with. The inference rules are commonly specified by means of an ontology language, and often a description language. Many reasoners use first-order predicate logic to perform reasoning; inference commonly proceeds by forward chaining and backward chaining. There are also examples of probabilistic reasoners, including Pei Wang's non-axiomatic reasoning system, Novamente's probabilistic logic network, and Pronto - probabilistic description logic reasoner.

List of semantic reasoners

Existing semantic reasoners and related software:

Commercial software

• Bossam (software), an RETE-based rule engine with native supports for reasoning over OWL ontologies, SWRL rules, and RuleML rules.
• DLog, Resolution based Description Logic ABox reasoner that translates to Prolog (DLog).
• OntoBroker, highly scalable SemanticWeb middleware (OntoBroker).
• OWLIM, a high-performance semantic repository developed in Java and available in three versions: OWLIM-lite (which is free to download and use) and the commercial OWLIM-se and OWLIM-enterprise. Supports OWL2-rl semantics, which can be configured through rule-set definition and selection. (OWLIM)
• RacerPro, a semantic web reasoning system and information repository (RacerPro)
• TopSPIN, rule-based reasoner embedded in TopBraid Suite support OWL 2 RL reasoning (TopBraid).
• SHER, a scalable Pellet-backed OWL DL reasoner (SHER).

Free to use (Closed Source)

• BaseVISor, a versatile forward chaining inference engine specialized to handle facts in the form of RDF triples with support for OWL 2 RL and XML Schema Datatypes (BaseVISor).
• Cyc inference engine, a forward and backward chaining inference engine with numerous specialized modules for high-order logic. ([1] ResearchCyc) ([2] OpenCyc)
• KAON2 is an infrastructure for managing OWL-DL, SWRL, and F-Logic ontologies.
• Hoolet, reasons over OWL-DL ontologies by translating them to full first-order logic and then applying a first-order theorem prover. (Hoolet)

Free Software (Open Source)

• Cwm, a forward-chaining reasoner which can be used for querying, checking, transforming and filtering information. Its core language is RDF, extended to include rules, and it uses RDF/XML or N3 serializations as required. (CWM, W3C software license)
• Drools, a forward chaining inference based rules engine that uses an enhanced implementation of the Rete algorithm. (Drools, Apache license 2.0)
• Euler (EYE), a RIF-compatible backward-chaining N3 reasoner enhanced with Euler path detection. (Euler Proof Mechanism, W3C software license)
• FaCT, a Lisp-based description logic (DL) classifier. (FaCT, GNU GPL)
• FaCT++, the new generation of FaCT OWL-DL reasoner, based on C++. (FaCT++, GNU Lesser GPL)
• Jena (framework), an open source semantic web framework for Java which includes a number of different semantic reasoning modules. (Apache Jena, Apache License 2.0)
• Large Knowledge Collider or LarKC is a large-scale distributed reasoner that focuses on performance by allowing incomplete reasoning (LarkC, Apache License 2.0)
• Pellet, an open-source Java OWL DL reasoner. (Pellet, AGPL version 3, commercial option available)
• Prova, an open-source Semantic Web rule engine which supports data integration via SPARQL queries and type systems (RDFS, OWL ontologies as type system). (Prova, GNU GPL v2, commercial option available)
• SweetRules, an integrated set of tools for Semantic web rules and ontologies. (SweetRules, GNU Lesser GPL)
• TopBraid SPIN API, API for SPIN, which is a collection of RDF vocabularies enabling the use of SPARQL to define constraints and inference rules on Semantic Web models. (SPIN API, GNU AGPL)
• HermiT, the first publicly available OWL reasoner based on a novel “hypertableau” calculus which provides much more efficient reasoning than any previously known algorithm. (HermiT, GNU Lesser GPL)

Reasoner comparison

	BaseVISor	Bossam	Cyc	Hoolet	Pellet	KAON2	RacerPro	Jena	FaCT	FaCT++	SweetRules	OWLIM	OntoBroker	HermiT
OWL-DL Entailment	No	Unknown	Yes	Yes	Yes	Yes	Yes	No complete reasoner included with standard distribution	Yes	Yes	No	No	Yes	Yes
Supported expressivity for reasoning	R-entailment, OWL 2 RL	Unknown	High-order	Unknown	SROIQ(D)	SHIQ(D)	SHIQ(D-)	varies by reasoner (incomplete for nontrivial description logics)	SHIQ	SROIQ(D)	Unknown	R-entailment, OWL 2 RL	OWL: SHIQ(D) (for OntoBroker 6.1: Subset of OWL-RL); F-logic: normal logic, wellfounded semantics	SHOIQ+
Reasoning algorithm	Rule-based, Rete	Rule-based	First-order with high-order extensions	First-order prover	Tableau	Resolution & Datalog	Tableau	Rule-based	Tableau	Tableau	Rule-based	Rule-based	OWL: Resolution & Datalog; F-logic: Rule-based (BottomUp, MagicSet, Dynamic-Filtering, QSQ)	Hypertableau
Consistency checking	Yes	Unknown	Yes	Yes	Yes	Yes	Yes	Incomplete for OWL DL	Yes	Yes	No	Yes	Yes	Yes
DIG Support	No	No	No	No	Deprecated	Deprecated	Deprecated	Yes	Yes	Yes	No	No	Yes	No
Rule Support	Yes (Own rule format)	Yes (SWRL & own rule format)	Yes (Own rule format)	Yes (SWRL)	Yes (SWRL—DL Safe Rules)	Yes (SWRL—DL Safe Rules)	Yes (SWRL—not fully supported) & own rule format	Yes (Own rule format)	No	No	Yes (SWRL, RuleML, Jess)	Yes (Own format)	Yes (SWRL, RIF, F-logic, ObjectLogic)	Yes (SWRL—DL Safe Rules)
Version	2.0	0.9b45	Unknown	Unknown	2.0.2	2008-06-29	2.0 preview	2.5.4	Unknown	1.6.0	2.1	2.x/3.x	6.1	1.3.6
Licensing	Free to use / closed-source	Free to use / closed-source	Free to use / closed-source (academic and research only) & Non-Free / closed-source	Free / open-source	Free / open-source & Non-Free/ closed-source	Free to use / closed-source	Non-Free/ closed-source	Free / open-source	Free / open-source	Free / open-source	Free / open-source	Non-Free/ closed-source	Non-Free/ closed-source	Free / open-source

See also

• Business rules engine
• Expert systems
• Doxastic logic
• Method of analytic tableaux

External links

• OWL 2 Reasoners listed on W3C OWL Working Group homepage
• SPARQL Query Language for RDF
• Introduction to Description Logics DL course by Enrico Franconi, Faculty of Computer Science, Free University of Bolzano, Italy
• Inference using OWL 2.0 Semantics by Craig Trim (IBM).
• Marko Luther, Thorsten Liebig, Sebastian Böhm, Olaf Noppens: Who the Heck Is the Father of Bob?. ESWC 2009: 66-80
• Jurgen Bock, Peter Haase, Qiu Ji, Raphael Volz. Benchmarking OWL Reasoners. In ARea2008 - Workshop on Advancing Reasoning on the Web: Scalability and Commonsense (June 2008)
• Tom Gardiner, Ian Horrocks, Dmitry Tsarkov. Automated Benchmarking of Description Logic Reasoners. Description Logics Workshop 2006
• OpenRuleBench Senlin Liang, Paul Fodor, Hui Wan, Michael Kifer. OpenRuleBench: An Analysis of the Performance of Rule Engines. 2009. Latest benchmarks at OpenRuleBench website.
• Pronto, a probabilistic description logic reasoner.