Dotan Cohen schrieb: > (%i1) M=matrix([1,2],[3,4]); ^ > [ 1 2 ] > (%o1) M = [ ] > [ 3 4 ] > (%i2) LU_FACTOR (M); > (%o2) LU_FACTOR(M) > Why doesn't it work when I use the identifier (variable name M)? The assignment operator in Maxima is ":", not "=". Kind regards Uwe