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D.5.4.17 makePDivisor
Procedure from librarydivisors.lib (see divisors_lib).
- Usage:
- makePDivisor(L); L = list.
- Assume:
- L is a list of tuples of a integral polyhedron and a divisor such that
all polyhedra have the same tail cone.
- Return:
- a pdivisor on X
- Theory:
- Represents an polyhedral formal sum of divisors.
LIB "divisors.lib"; ring r=31991,(x,y,z),dp; ideal I = y^2*z - x*(x-z)*(x+3*z); qring Q = std(I); divisor A = makeDivisor(ideal(x,z),ideal(1)); divisor B = makeDivisor(ideal(x,y),ideal(1)); intmat M[4][4]= 1,4,0,0, 1,0,3,0, 0,0,0,2, 1,1,1,1; polytope PP = polytopeViaPoints(M); makePDivisor(list(list(PP,A),list(PP,B))); ==> tail=<cone> ==> summands=<list> |