We study idempotent analogs of topological tensor products in the sense of A. Grothendieck. The basic concepts and results are simulated on the algebraic level. This is one of a series of papers on idempotent functional analysis.

In this paper we characterize those hemirings for which each k-ideal is idempotent. We also characterize those hemirings for which each fuzzy k-ideal is idempotent. The space of prime k-ideals (fuzzy k-prime k-ideals) is topologized.

The concept of idempotent elements plays an important role in semigroup theory and semiring theory. In this paper we characterize idempotent pre-generalized hypersubstitutions of type τ = (2, 2).

A unifying approach to software and hardware design generated by ideas of Idempotent Mathematics is discussed. The so-called idempotent correspondence principle for algorithms, programs and hardware units is described. A software project based on this approach is presented.

In this paper, we present necessary and sufficient conditions for X? to be idempotent orthogonal idempotent, where ? {A?, AD, AD?, A?,D Aw}. Several characteristics when is are derived by core-EP decomposition. Additionally, give some equivalent matrix A using the properties of generalized inverses A.