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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