fspace.spad line 372 [edit on github]
This package allows a mapping E -> F to be lifted to a kernel over E; This lifting can fail if the operator of the kernel cannot be applied in F; Do not use this package with E = F, since this may drop some properties of the operators.
map(f, k) returns g = op(f(a1), ..., f(an)) where k = op(a1, ..., an).