The 3x3 lemma in the ${\Sigma}$-Maltsev and ${\Sigma}$-protomodular settings. Applications to monoids and quandles

Abstract

We investigate what is remaining of the 3x3 lemma and of the denormalized 3x3 lemma, respectively valid in a pointed protomodular and in a Maltsev category, in the context of partial pointed protomodular and partial Maltsev categories, relatively to a class ${\Sigma}$ of points. The results apply, among other structures, to monoids, semirings and quandles