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D.4.24.7 regCM

Procedure from library noether.lib (see noether_lib).

Usage:
regCM (i); i ideal

Return:
the Castelnuovo-Mumford regularity of i.
(returns -1 if i is not homogeneous)

Assume:
i is a homogeneous ideal.

Example:
 
LIB "noether.lib";
ring r=0,(t,a,b,c,d),dp;
ideal i=b4-a3d, ab3-a3c, bc4-ac3d-bcd3+ad4, c6-bc3d2-c3d3+bd5, ac5-b2c3d-ac2d3+b2d4, a2c4-a3d3+b3d3-a2cd3, b3c3-a3d3, ab2c3-a3cd2+b3cd2-ab2d3, a2bc3-a3c2d+b3c2d-a2bd3, a3c3-a3bd2, a4c2-a3b2d;
regCM(i);
==> reg(i)=7 and the time of this computation: 3 sec./100