# Resource Description Framework (RDF)

RDF (wikipedia entry) is a first order logic for the web built on Graphs. See the paper by Tim Berners-Lee et al. N3Logic: A logical framework for the World Wide Web. Category Theory also builds on Graphs. Indeed any Graph gives rise to the Free Category of that Graph. It is quite important thus to understand how the two are related.

One major problem that needs to be resolved is how the Dataset construct in RDF1.1 that was first used by N3 and as Named Graphs in SPARQL fits in, as these seem to require something like graphs inside graphs. These don't have a formally agreed semantics. Yet, usage shows that N3 Graphs can be used for modal logic, opaque contexts, etc... hence the interest below in how Cats deal with modal logics.

# RDF and Cats papers

A number of papers address directly the relation of RDF to Cats.

# RDF, Contexts and Modal Logic

The following papers look at RDF and modal logic but without bringing Category Theory into the Picture

The slogan here is that, where HoTT itself is the internal language of(∞,1)-toposes, modal HoTT is the internal language for collections of(∞,1)-toposes related by geometric morphisms

More references on the Adjoint Logic page on nlab wiki and links from there.