Lambda the Ultimate

This 10-page 1992 article, Towards Applicative Relational Programming by Ibrahim & van Enden, has just appeared on ArXiv, which asked the question of how to combine functional and relational programming.

This is fairly well-trodden ground now, with approaches such as Miller's lambda-Prolog and Saraswat's constraint-lambda calculus being well establsihed, but this paper offers a rather different approach, based on the Henkin-Monk-Tarski approach of cylindric algebras, which were devised as a means of formalising predicate logic in equational logic - I'm familiar with them in the context of modal logic, since they offer a means for handling quantifiers by means of modalities, where [] is used to express forall and <> is used to express exists.

The treatment is nice, and is recommended to LtUers interested in having an arsenal of techniques for bridging the declarative divide.

For those of you still looking, here's a fun introduction to Category Theory by Barry Mazur.