A Pseudo Representation Theorem for Various Categories of Relations

It is well-known that, given a Dedekind categoryR the category of (typed) matrices with coefficients from R is a Dedekind category with arbitrary relational sums. In this paper we show that under slightly stronger assumptions the converse is also true. Every atomic Dedekind category R with relational sums and subobjects is equivalent to a category of matrices over a suitable basis. This basis is the full proper subcategory induced by the integral objects of R. Furthermore, we use our concept of a basis to extend a known result from the theory of heterogeneous relation algebras.