subst

[Markus Endres <me@mendres.org>]

hallo at all,

I have the following situation:

I want to substitute the variable x in a polmod through y like this:

? subst(Mod(1,z^2+19)*x, x, y)
%53 = Mod(y, z^2 + 19)
? 

I expect Mod(1,z^2+19)*y (this I need!) but get something strange (for
me) like Mod(y, z^2+19).

Now, why do I get this "wrong" result and how do I get the right one?

thanks in advance

cheers

me