7.3.27 subst (plural)

Syntax:

subst ( poly_expression,ring_variable, poly_expression )
subst ( vector _expression,ring_variable, poly_expression )
subst ( ideal_expression,ring_variable, poly_expression )
subst ( module _expression,ring_variable, poly_expression )

Type:

poly, vector, ideal or module (corresponding to the first argument)

Purpose:

substitutes a ring variable by a polynomial.

Example:

LIB "ncalg.lib"; def R = makeUsl2(); // this algebra is U(sl_2) setring R; poly C = e*f*h; poly C1 = subst(C,e,h^3); C1; ==> fh4-6fh3+12fh2-8fh poly C2 = subst(C,f,e+f); C2; ==> e2h+efh