manip.spad line 39 [edit on github]
numer : % -> P
denom : % -> P
coerce : P -> %
computes n-th roots of quotients of multivariate polynomials
froot(f, n) returns [m, c, r] such that f^(1/n) = c * r^(1/m).
nthr(p, n) should be local but conditional
qroot(f, n) returns [m, c, r] such that f^(1/n) = c * r^(1/m).
rroot(f, n) returns [m, c, r] such that f^(1/n) = c * r^(1/m).