Singular Manual: isAface

| #### D.15.12.5 isAface Procedure from library `gitfan.lib` (see gitfan_lib). Usage: isAface(a,gam0); a: ideal, gam0:intvec Purpose: Checks whether the face of the positive orthant, that is spanned by all i-th unit vectors, where i ranges amongst the entries of gam0, is an a-face. Return: int Example:
    LIB "gitfan.lib";
    ring R = 0,(T(1..4)),dp;
    ideal I = T(1)*T(2)-T(4);
    intvec w = 1,4;
    intvec v = 1,2,4;
    isAface(I,w); // should be 0
    ==> 0
    "-----------";
    ==> -----------
    isAface(I,v); // should be 1
    ==> 1

User manual for Singular version 4-1-0, 2016, generated by texi2html.