Hello, how to simplify matrix equation 'e2' to obtain back 'e1' ? A,B,C are matrices. matrix_element_mult: "."$ e1: A.(B+C); /* A . (C + B) */ e2: expand(e1); /* A . C + A . B */ How to obtain from 'e2' result given in 'e1' ? ratsimp(e2); <-- do not work Thank you in advance ? Zbigniew