File src/mat.red artifact 24a6c2b757 part of check-in c1ddb4c814

% example for matrix inversion
mm:=mat ((1, 19, 9, 5),
(5, 17, 7, 11),
(9, 13, 11, 17),
(13, 7, 15, 19));
mminv:=1/mm;
end;