A broad definition for the concept of "semantics" as applied to the Semantic Web has been provided by Sheth et al. (2005), in terms of three types of semantics:

  • Implicit semantics. "This type of semantics refers to the kind that is implicit in data and that is not represented explicitly in any machine processable syntax."
  • Formal semantics. "Semantics that are represented in some well-formed syntactic form (governed by syntax rules) is referred to as formal semantics."
  • Powerful (soft) semantics. "Usually, efforts related to formal semantics have involved limiting expressiveness to allow for acceptable computational characteristics. Since most KR mechanisms and the Relational Data Model are based on set theory, the ability to represent and utilize knowledge that is imprecise, uncertain, partially true, and approximate is lacking, at least in the base/standard models. [...] Representing and utilizing these types of more powerful knowledge is, in our opinion, critical to the success of the Semantic Web. Soft computing has explored these types of powerful semantics. We deem these powerful (soft) semantics as distinguished, albeit not distinct from or orthogonal to formal and implicit semantics."

The three types of semantics are included in the focus of MTSR'05.



Sheth, A. et al.(2005). Semantics for the Semantic Web: The Implicit, the Formal and the Powerful. Intl. Journal on Semantic Web and Information Systems 1(1), 1-18.