5.1.92 mpresmat

Syntax:

mpresmat ( ideal_expression, int_expression )

Type:

module

Purpose:

computes the multipolynomial resultant matrix of the input system. Uses the sparse resultant matrix method of Gelfand, Kapranov and Zelevinsky (second parameter = 0) or the resultant matrix method of Macaulay (second parameter = 1).

Note:

When using the resultant matrix method of Macaulay the input system must be homogeneous. The number of elements in the input system must be the number of variables in the basering plus one.

Example:

ring rsq=(0,s,t,u),(x,y),lp; ideal i=s+tx+uy,x2+y2-10,x2+xy+2y2-16; module m=mpresmat(i,0); print(m); ==> -16,0, -10,0, (s),0, 0, 0, 0, 0, ==> 0, -16,0, -10,(u),(s),0, 0, 0, 0, ==> 2, 0, 1, 0, 0, (u),0, 0, 0, 0, ==> 0, 2, 0, 1, 0, 0, 0, 0, 0, 0, ==> 0, 0, 0, 0, (t),0, -10,(s),0, -16, ==> 1, 0, 0, 0, 0, (t),0, (u),(s),0, ==> 0, 1, 0, 0, 0, 0, 1, 0, (u),2, ==> 1, 0, 1, 0, 0, 0, 0, (t),0, 0, ==> 0, 1, 0, 1, 0, 0, 0, 0, (t),1, ==> 0, 0, 0, 0, 0, 0, 1, 0, 0, 1