Derived and stable equivalences of centralizer matrix algebras

Abstract: The centralizer of a matrix in a full matrix algebra is called a principal centralizer matrix algebra. Characterizations are presented for principal centralizer matrix algebras to be Morita equivalent, almost $\nu$-stable derived equivalent, derived equivalent, and stably equivalent of Morita type, respectively, in terms of new equivalence relations on square matrices. These equivalence relations on matrices are introduced in a natural way by their elementary divisors. Thus the categorical equivalences are reduced to questions in linear algebra. Consequently, principal centralizer matrix algebras of permutation matrices are Morita equivalent if and only if they are derived equivalent. Moreover, two representation-finite, principal centralizer matrix algebras over a perfect field are stably equivalent of Morita type if and only if they are stably equivalent. Further, derived equivalences between the principal centralizer matrix algebras of permutation matrices induce the ones of their $p$-regular parts and $p$-singular parts of the given permutations.