Editing Semantic Web (section)

=== Components ===
The term "Semantic Web" is often used more specifically to refer to the formats and technologies that enable it.<ref name="W3C-SWA" /> The collection, structuring and recovery of linked data are enabled by technologies that provide a [[description logic|formal description]] of concepts, terms, and relationships within a given [[knowledge domain]]. These technologies are specified as W3C standards and include:
* [[Resource Description Framework]] (RDF), a general method for describing information
* [[RDF Schema]] (RDFS)
* [[Simple Knowledge Organization System]] (SKOS)
* [[SPARQL]], an RDF query language
* [[Notation3]] (N3), designed with human readability in mind
* [[N-Triples]], a format for storing and transmitting data
* [[Turtle (syntax)|Turtle]] (Terse RDF Triple Language)
* [[Web Ontology Language]] (OWL), a family of [[knowledge representation language]]s
* [[Rule Interchange Format]] (RIF), a framework of web rule language dialects supporting rule interchange on the Web
* [[JSON-LD|JavaScript Object Notation for Linked Data]] (JSON-LD), a JSON-based method to describe data
* [[ActivityPub]], a generic way for client and server to communicate with each other. This is used by the popular decentralized social network [[Mastodon (software)|Mastodon]].

The [[Semantic Web Stack]] illustrates the architecture of the Semantic Web. The functions and relationships of the components can be summarized as follows:<ref>{{cite web |url=http://www.w3.org/TR/owl-features/ |title=OWL Web Ontology Language Overview |date=February 10, 2004 |publisher=World Wide Web Consortium (W3C) |access-date=November 26, 2011}}</ref>
* XML provides an elemental syntax for content structure within documents, yet associates no semantics with the meaning of the content contained within. XML is not at present a necessary component of Semantic Web technologies in most cases, as alternative syntaxes exist, such as [[Turtle (syntax)|Turtle]]. Turtle is a de facto standard, but has not been through a formal standardization process.
* [[W3C XML Schema|XML Schema]] is a language for providing and restricting the structure and content of elements contained within XML documents.
* RDF is a simple language for expressing [[data model]]s, which refer to objects ("[[web resource]]s") and their relationships. An RDF-based model can be represented in a variety of syntaxes, e.g., [[RDF/XML]], N3, Turtle, and RDFa. RDF is a fundamental standard of the Semantic Web.<ref>{{cite web|url=http://www.w3.org/RDF/ | title=Resource Description Framework (RDF) | publisher=[[World Wide Web Consortium]]}}</ref><ref>{{cite book |last1=Allemang |first1=Dean |last2=Hendler |first2=James |last3=Gandon |first3=Fabien |title=Semantic Web for the Working Ontologist : Effective Modeling for Linked Data, RDFS, and OWL |date=August 3, 2020 |publisher=ACM Books; 3rd edition |location=[New York, NY, USA] |isbn=978-1450376143 |edition=Third}}</ref>
* RDF Schema extends RDF and is a vocabulary for describing properties and classes of RDF-based resources, with semantics for generalized-hierarchies of such properties and classes.
* OWL adds more vocabulary for describing properties and classes: among others, relations between classes (e.g. disjointness), cardinality (e.g. "exactly one"), equality, richer typing of properties, characteristics of properties (e.g. symmetry), and enumerated classes.
* SPARQL is a protocol and query language for semantic web data sources.
* RIF is the W3C Rule Interchange Format. It is an XML language for expressing Web rules that computers can execute. RIF provides multiple versions, called dialects. It includes a RIF Basic Logic Dialect (RIF-BLD) and RIF Production Rules Dialect (RIF PRD).