7.2.6.1 resolution declarations (plural)

Syntax:

resolution name = resolution_expression ;

Purpose:

defines a resolution.

Default:

none

Example:

ring r=0,(x,y,z),dp; matrix D[3][3]; D[1,2]=z; def R=nc_algebra(1,D); // it is a Heisenberg algebra setring R; ideal i=z2+z,x+y; resolution re=nres(i,0); re; ==> 1 2 1 ==> R <-- R <-- R ==> ==> 0 1 2 ==> resolution not minimized yet ==> list l = re; l; ==> [1]: ==> _[1]=z2+z ==> _[2]=x+y ==> [2]: ==> _[1]=z2*gen(2)-x*gen(1)-y*gen(1)+z*gen(2) ==> [3]: ==> _[1]=0 print(matrix(l[2])); ==> -x-y, ==> z2+z print(module(transpose(matrix(l[2]))*transpose(matrix(l[1])))); // check that product is zero ==> 0