D.5.9.1 isCMcod2

Procedure from library spcurve.lib (see spcurve_lib).

Usage:

isCMcod2(i); i an ideal

Return:

presentation matrix of i, if i is Cohen-Macaulay of codimension 2
a zero matrix otherwise

Example:

LIB "spcurve.lib";
ring r=32003,(x,y,z),ds;
ideal i=xz,yz,x^3-y^4;
print(isCMcod2(i));
→ -y,-x2,
→ x, y3, 
→ 0, z