next | previous | forward | backward | up | top | index | toc | Macaulay2 web site
Seminormalization :: findElementMappingToTarget

findElementMappingToTarget -- given a ring map and an element of the target, this find an element from the source whose image is the given one

Synopsis

Description

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

Ways to use findElementMappingToTarget :