I want to conjugate a symbolic matrix, Sigma, by a matrix, garbage, over Z/9Z. If I define both matrices as symbolic matrices, I get the right answer. If I define garbage over Z/9Z, I get confusing answers. Can anyone explain my results?
Sigma=matrix(SR,2,[[1+3A,3B],[3C,1+3D]]) garbage=matrix(SR,2,[[2,1],[2,6]]);garbageinverse=matrix(SR,2,[[6,8],[7,2]]) expand(garbageSigmagarbageinverse);(Sigmagarbageinverse)[0,0]garbage[1,0]+(Sigmagarbageinverse)[1,0]garbage[1,1] R=Integers(9) garbage=matrix(R,2,[[2,1],[2,6]]);garbageinverse=matrix(R,2,[[6,8],[7,2]]) expand(garbageSigmagarbageinverse);(Sigmagarbageinverse)[0,0]garbage[1,0]+(Sigmagarbageinverse)[1,0]garbage[1,1]
[ 36A + 42B + 18C + 21D + 19 48A + 12B + 24C + 6D + 18] [36A + 42B + 108C + 126D + 54 48A + 12B + 144C + 36D + 28] 36A + 42B + 108C + 126D + 54 [ 6B + 3D + 1 3A + 3B + 6C + 6D] [ 0A + 0D 3A + 0D + 1] 6B + 0D