Given a ring map φ: R →S and y ∈S, this finds x ∈R such that φ(x) = y (if it exists). If no such element exists, it throws an error.
i1 : R = QQ[u,v, w]; |
i2 : S = QQ[a,b]; |
i3 : phi = map(S, R, {a, a*b, 0}); o3 : RingMap S <--- R |
i4 : findElementMappingToTarget(phi, a) o4 = u o4 : R |
i5 : findElementMappingToTarget(phi, sub(0, S)) o5 = 0 o5 : R |