Tensor products of bimodules over monoids

Abstract

We modify the well-known tensor product of modules over a semiring, in order to treat modules over hyperrings, and, more generally, for bimodules (and bimagmas) over monoids. The tensor product of residue hypermodules is functorial. Special attention is paid to different kinds of morphisms and the work of Nakamura and Reyes.

20 pages. Expanded introduction. More information about homomorphisms, and about the residue hypermodules is included in this version