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, 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).
Flora-2, an object-oriented, rule-based knowledge-representation and reasoning system.
Jena, 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, 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 reasoner and Protégé desktop plugin for representing and reasoning with defeasible subsumption.[3] It implements a Preferential entailment 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) is a rule-based reasoning engine and an approach for sharing and reusing interoperable rules to deduce meaningful knowledge from sensor measurements.
^Goertzel, Ben; Iklé, Matthew; Goertzel, Izabela Freire; Heljakka, Ari (2008). Probabilistic Logic Networks: A Comprehensive Framework for Uncertain Inference. Springer Science & Business Media. p. 42. ISBN978-0-387-76872-4.
^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.