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D.15.18.3 fullDimImages

Procedure from library gitfan.lib (see gitfan_lib).

Usage:
fullDimImages(afaces, Q); afaces: list, Q: intmat

Purpose:
Determines the a-faces (represented as intvecs) from the list afaces which have a full-dimensional projection with respect to Q.

Return:
a list of intvecs

Example:
 
LIB "gitfan.lib";
ring R = 0,T(1..10),wp(1,1,1,1,1,1,1,1,1,1);
ideal J =
T(5)*T(10)-T(6)*T(9)+T(7)*T(8),
T(1)*T(9)-T(2)*T(7)+T(4)*T(5),
T(1)*T(8)-T(2)*T(6)+T(3)*T(5),
T(1)*T(10)-T(3)*T(7)+T(4)*T(6),
T(2)*T(10)-T(3)*T(9)+T(4)*T(8);
intmat Q[5][10] =
1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 1, 1, 0, 0, 0,
0, 1, 1, 0, 0, 0, -1, 1, 0, 0,
0, 1, 0, 1, 0, -1, 0, 0, 1, 0,
0, 0, 1, 1, -1, 0, 0, 0, 0, 1;
list AF= afaces(J,nrows(Q));
size(AF);
==> 81
size(fullDimImages(AF,Q));
==> 36