Function: substvec
Section: polynomials
C-Name: gsubstvec
Prototype: GGG
Help: substvec(x,v,w): in expression x, make a best effort to replace the
variables v1,...,vn by the expression w1,...,wn.
Doc: $v$ being a vector of monomials of degree 1 (variables),
$w$ a vector of expressions of the same length, replace in the expression
$x$ all occurrences of $v_i$ by $w_i$. The substitutions are done
simultaneously; more precisely, the $v_i$ are first replaced by new
variables in $x$, then these are replaced by the $w_i$:
\bprog
? substvec([x,y], [x,y], [y,x])
%1 = [y, x]
? substvec([x,y], [x,y], [y,x+y])
%2 = [y, x + y] \\ not [y, 2*y]
@eprog