Recently, there has been a significant interest in the combinatorial properties the ring of n×n matrices. The aim of this note is to describe a short (may be the shortest possible) presentation of the matrix ring Matn(Z). This presentation is significantly shorter than the previously known ones, see [7]. Surprisingly, the number of relations in the presentation does not depend on the size of th...

let r be a ring and v be a matrix valuation on r. it is shown that, there exists a correspondence between matrix valuations on r and some special subsets ?(mvpr) of the set of all square matrices over r, analogous to the correspondence between invariant valuation rings and abelian valuation functions on a division ring. furthermore, based on malcolmson’s localization, an alternative proof for t...

we introduce the class of “right almost v-rings” which is properly between the classes of right v-rings and right good rings. a ring r is called a right almost v-ring if every simple r-module is almost injective. it is proved that r is a right almost v-ring if and only if for every r-module m, any complement of every simple submodule of m is a direct summand. moreover, r is a right almost v-rin...