The World Wide Web Consortium (W3C), is the governing standards body for the Web, including the Semantic Web. The Semantic Web is often depicted graphically as a “Layer Cake”.
    There are many versions of the “layer cake diagram” that illustrates the standards and their roles, such as this, published by the W3C.

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    Here, we address the lower parts of the cake, i.e. URIs, RDF, RDFS, SPARQL and OWL. “Rules” are now well-developed in the semantic web standards stack; but the notions of “Crypto”, “Unifying Logic” , “Proof” and “Trust” remain active research in Semantic Web as well as the broader research community and Web standards development.