![]() | 1 | initial version |
A map from Q[w2,w1,x,y] to Q[w1,x,y] is always going to be tricky because it's just a partial map. I don't know why the block order gets in the way, but it's not hard to work around it:
sage: S(QQ['w1,x,y'](f2))
w1*x^3 + w1*y + x^2 + y^2