7.3.9 intersect (plural)

Syntax:

intersect (expression_list of ideal_expression )
intersect (expression_list of module_expression )

Type:

ideal, resp. module

Purpose:

computes the intersection of ideals, resp. modules.

Example:

ring r=0,(x,y),dp; def R=nc_algebra(-1,0); //anti-commutative algebra setring R; module M=[x,x],[y,0]; module N=[0,y^2],[y,x]; option(redSB); module Res; Res=intersect(M,N); print(Res); ==> y2, 0, ==> -xy,xy2 kill r,R; //-------------------------------- LIB "ncalg.lib"; ring r=0,(x,d),dp; def RR=Weyl(); // make r into Weyl algebra setring RR; ideal I = x+d^2; ideal J = d-1; ideal H = intersect(I,J); H; ==> H[1]=d4+xd2-2d3-2xd+d2+x+2d-2 ==> H[2]=xd3+x2d-xd2+d3-x2+xd-2d2-x+1