[Sem] Syntax and model-theoretic semantics: a complete proposal

I extended my original proposal to include a fully opaque case, so that it can represent both the fully opaque case (syntactic predication) and the fully transparent case (semantic and modal predications).
Now the proposal comes with a completely specified abstract semantics, etc.
This proposal comes in three flavours, depending on the syntax chosen:

  1.  the Community Group syntax with TEP as it is described in its final report (wiki: CG syntax specification<https://github.com/w3c/rdf-star-wg/wiki/Semantics-(CG-syntax)-by-enrico>),
  2.  the variant which distinguishes syntactic from semantic quoted triples (wiki: alt syntax specification<https://github.com/w3c/rdf-star-wg/wiki/Semantics-(alt-syntax)-by-enrico>),
  3.  the variant with a quoting operator which gives a syntactic reading to arbitrary terms (wiki: alt syntax with quoted terms specification<https://github.com/w3c/rdf-star-wg/wiki/Semantics-(alt-syntax-with-quoted-terms)-by-enrico>).

There is a wiki page describing each variant of the proposal.
—e.