Abstract
Let denote an algebraically closed field, and let x, y, z be the equitable generators of over . Let V denote a finite-dimensional irreducible -module, let be a linear map. We show that if any two of the matrices representing with respect to a standard x-, y- and z-eigenbasis are tridiagonal, then acts as a linear combination of 1, x, y, z, xy, zx, yz and yzx.