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NormalToricVarieties :: isQQCartier

isQQCartier -- whether a torus-invariant Weil divisor is QQ-Cartier

Synopsis

Description

A Weil divisor is -Cartier if some positive integer multiple is Cartier.

On a simplicial toric variety, every torus-invariant Weil divisor is -Cartier.

W = weightedProjectiveSpace {2,5,7};
isSimplicial W
isCartier W_0
isQQCartier W_0
isCartier (35*W_0)
In general, the -Cartier divisors form a proper subgroup of the Weil divisors.
X = normalToricVariety(id_(ZZ^3) | -id_(ZZ^3));
isCartier X_0
isQQCartier X_0
K = toricDivisor X
isCartier K

See also

Ways to use isQQCartier :