Axiomatizing generalized subreducts of RRA 
Szabolcs Mikulas

We will consider signatures consisting of operations definable in
representable relation algebras, RRAs, and look at the problem of
axiomatizing the corresponding fragments of RRA.
In particular, we will focus on signatures that include the residuals
of relation composition and/or the domain operation and give a survey
of results about finitely axiomatizing the generated varieties and
quasi-varieties.