What kind of Algebra would RDF be?

[bblfish]

Kohei Kishida's article "Categories and Modalities" in Categories for the Working Philosopher, starts with a section "Syntax, Semantics and Duality" and explains how one thinks of logic algebraically.

RDF is a first order logic, but one should be able to take the structure of inference between Graphs and find this to be equivalent to a propositional logic of some form. Would it fit a Boolean Algebra, a Heyting Algebra, or something else?

We do seem to have a

• G1∧G2≈G3 where G3 is the merging of those graphs.
• G1⋁G2≈G3 where G3 is the intersection of those graphs, taking into account bnodes in Braatz's RDFHom
• Do we have implication? In RDFHom that is graph morphisms.
• Do we have negation? (I guess no)
• do we have ⟘ or ⟙?