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D.15.1.12 arrCentered
Procedure from libraryarr.lib (see arr_lib).
- Usage:
- arrCentered(A); arr A
- Return:
- [0,1] true if A is centered(i.e. intersection of all planes not empty)
- Note:
- The algorithm uses the rank of matrix: Ax=b has a solution iff rank(A) = rank(A|b)
LIB "arr.lib"; ring R = 0,(x,y,z),dp; arr A= ideal(x,y,x-y+1); // centerless arrCentral(A); ==> 0 arr B= ideal(x,y,z); // central with center being the origin arrCentral(B); ==> 1 arr C= ideal(x+1,2y+1,-z+1); // central with center (-1,-1/2, 1) arrCentral(C); ==> 0 |