# Operations on Matrix Algebras

## `Centre(A): AlgMat -> AlgMat`

Given a matrix algebra $A$ whose base ring is a field, return the centre of $A$.

## `Centralizer(A, S): AlgMat, AlgMat -> AlgMat`

## `Centraliser(A, S): AlgMat, AlgMat -> AlgMat`

Given a matrix algebra $A$ whose base ring is a field, together with a subalgebra $S$ of $A$ return the centralizer of $S$ in $A$.