A semantic reasoner, reasoning engine, rules engine, or simply a reasoner, is a piece of software able to infer

logical consequence Logical consequence (also entailment or logical implication) is a fundamental concept in logic which describes the relationship between statement (logic), statements that hold true when one statement logically ''follows from'' one or more stat ...

s from a set of asserted facts or

axioms An axiom, postulate, or assumption is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. The word comes from the Ancient Greek word (), meaning 'that which is thought worthy or f ...

. 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 logic Description logics (DL) are a family of formal knowledge representation languages. Many DLs are more expressive than propositional logic but less expressive than first-order logic. In contrast to the latter, the core reasoning problems for DLs are ...

language. Many reasoners use first-order predicate logic to perform reasoning;

inference Inferences are steps in logical reasoning, moving from premises to logical consequences; etymologically, the word '' infer'' means to "carry forward". Inference is theoretically traditionally divided into deduction and induction, a distinct ...

commonly proceeds by forward chaining and backward chaining. There are also examples of probabilistic reasoners, including non-axiomatic reasoning systems, and probabilistic logic networks.

Notable applications

Notable semantic reasoners and related software:

Free to use (closed source)

Cyc Cyc (pronounced ) is a long-term artificial intelligence (AI) project that aims to assemble a comprehensive ontology and knowledge base that spans the basic concepts and rules about how the world works. Hoping to capture common sense knowledge ...

inference engine, a forward and backward chaining inference engine with numerous specialized modules for high-order logic. * KAON2 is an infrastructure for managing OWL-DL, SWRL, and

F-Logic F-logic (Frame logic) is a knowledge representation and ontology language. It combines the advantages of conceptual modeling with Object-oriented programming, object-oriented, Frame (artificial intelligence), frame-based languages, and offers a Decl ...

ontologies.

Free software (open source)

* Cwm, a forward-chaining reasoner 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. *

Drools Drools is a business rule management system (BRMS) with a forward and backward chaining inference-based rules engine, more correctly known as a production rule system, using an enhanced implementation of the Rete algorithm. Drools support ...

, a forward-chaining inference-based rules engine which uses an enhanced implementation of the Rete algorithm.
Evrete
a forward-chaining Java rule engine that uses the Rete algorithm and is compliant with the Java Rule Engine API (JSR 94). * D3web, a platform for

knowledge-based systems A knowledge-based system (KBS) is a computer program that reasons and uses a knowledge base to solve complex problems. Knowledge-based systems were the focus of early artificial intelligence researchers in the 1980s. The term can refer to a b ...

(

expert systems In artificial intelligence (AI), an expert system is a computer system emulating the decision-making ability of a human expert. Expert systems are designed to solve complex problems by Automated reasoning system, reasoning through bodies of knowl ...

). *

Flora-2 Flora-2 is an open source semantic rule-based system for knowledge representation and reasoning. The language of the system is derived from F-logic, HiLog, W. Chen, M. Kifer and D.S. Warren (1993)''HiLog: A Foundation for Higher-Order Logic Program ...

, an object-oriented, rule-based knowledge-representation and reasoning system. *

Jena Jena (; ) is a List of cities and towns in Germany, city in Germany and the second largest city in Thuringia. Together with the nearby cities of Erfurt and Weimar, it forms the central metropolitan area of Thuringia with approximately 500,000 in ...

, an open-source semantic-web framework for Java which includes a number of different semantic-reasoning modules.
OWLSharp
a lightweight and friendly .NET library for realizing intelligent Semantic Web applications.
NRules
a forward-chaining inference-based rules engine implemented in C# which uses an enhanced implementation of the Rete algorithm *

Prova {{other uses Prova is an open source programming language that combines Prolog with Java. Description Prova is a rule-based scripting system that is used for middleware. The language combines imperative and declarative programming by using a p ...

, a semantic-web rule engine which supports data integration via SPARQL queries and type systems (RDFS, OWL ontologies as type system).
DIP
Defeasible-Inference Platform (DIP) is an

Web Ontology Language The Web Ontology Language (OWL) is a family of Knowledge representation and reasoning, knowledge representation languages for authoring Ontology (information science), ontologies. Ontologies are a formal way to describe Taxonomy, taxonomies and ...

reasoner and

Protégé Mentorship is the patronage, influence, guidance, or direction given by a mentor. A mentor is someone who teaches or gives help and advice to a less experienced and often younger person. In an organizational setting, a mentor influences the perso ...

desktop plugin for representing and reasoning with defeasible subsumption.Britz, K. and Varzinczak, I., (2018). Rationality and context in defeasible subsumption. In International Symposium on Foundations of Information and Knowledge Systems (pp. 114-132). Springer, Cham. It implements a

Preferential entailment Preferential entailment is a non-monotonic logic based on selecting only models that are considered the most plausible. The plausibility of models is expressed by an ordering among models called a preference relation, hence the name preference enta ...

style of reasoning that reduces to "classical entailment" i.e., without the need to modify the underlying decision procedure.

Semantic Reasoner for Internet of Things (open-source)

S-LOR (Sensor-based Linked Open Rules) semantic reasoner
S-LOR is under GNU GPLv3 license. S-LOR (Sensor-based Linked Open Rules) is a rule-based reasoning engine and an approach for sharing and reusing interoperable rules to deduce meaningful knowledge from sensor measurements.

References

External links

OWL 2 Reasoners listed on W3C SW Working Group homepage

SPARQL Query Language for RDF
* 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

Mirror available
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 {{Semantic Web Knowledge representation Knowledge engineering Ontology (information science) Semantic Web Automated reasoning