nefGenerators X
The nef cone of a variety is the cone generated by classes of nef Cartier divisors in vector space of Cartier divisors modulo numerical equivalence. On a normal toric variety, numerical equivalence and linear equivalence coincide, so the nef cone lies in the Picard group. Assume that the normal toric variety is non-degenerate, its nef cone is a rational polyhedral cone in the Picard group; see Theorem 6.3.20 in Cox-Little-Schenck's Toric Varieties. This function calculates generators for the rays of this cone, and returns a matrix whose columns correspond to these generates (expressed as vectors in the chosen basis for the Picard group).
For some of our favourite normal toric varieties, we choose a basis for the Picard group which makes the nef cone into the positive orthant.
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In general, the nef cone need not even be simplicial.
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