Semantic Web Language, SWL, First Order Logics, FOPL, syntax, semantic

The paper tries to discuss from a slightly higher level a focus oriented towards general properties that a Semantic Web Language (SWL) must have. We state as a ground the following two points of view: to compare 1. Expressivity of the SWL, and 2. a possibility to infer new knowledge from an SWL knowledge base with corresponding properties of the classical First Order Logics (FOPL) as a measure of their basic quality (now prepared). From expressivity, the language for the semantic web must be a common communication tool for computers as well as for people fulfilling an easy-to-use condition by means of adding more semantics directly into the language´s syntax. After a discussion of properties and critical recommendations two languages, OWL DL1 and RDF CFL have been proposed here to become the SWL both having the expressivity comparable with the FOPL.