Hi, I'm wondering what is going on here (ginsh output): > subs($1 * x + 1/2 * x^2 * $2, match(a * x + b, $1 + x * $2)); b*a+1/2*a^3 What happened to "x" ? The match by itself correctly finds > match(a * x + b, $1 + x * $2); {$2==a,$1==b} but the substitution result is weird. Greetings, Jan