next | previous | forward | backward | up | index | toc

# makeProductRing -- Makes the coordinate ring of a product of projective spaces.

## Synopsis

• Usage:
makeProductRing(n)
makeProductRing(kk,n)
• Inputs:
• n, a list, a list {n_1,...,n_m} of the dimensions of the m projective spaces in the product \PP^{n_1}x...x\PP^{n_m}.
• kk, a ring, the coefficient ring to be used
• Outputs:
• a ring, the graded coordinate ring of \PP^{n_1}x...x\PP^{n_m}.

## Description

Builds the multi-graded coordinate ring of \PP^{n_1}x...x\PP^{n_m}.

 i1 : R = makeProductRing(QQ,{3,4}) o1 = R o1 : PolynomialRing i2 : R = makeProductRing({3,4}) o2 = R o2 : PolynomialRing i3 : degrees R o3 = {{1, 0}, {1, 0}, {1, 0}, {1, 0}, {0, 1}, {0, 1}, {0, 1}, {0, 1}, {0, 1}} o3 : List i4 : gens R o4 = {a, b, c, d, e, f, g, h, i} o4 : List

## Ways to use makeProductRing :

• makeProductRing(List)
• makeProductRing(Ring,List)
• makeProductRing(Ring,Symbol,List) (missing documentation)
• makeProductRing(Symbol,List) (missing documentation)

## For the programmer

The object makeProductRing is .