Proof. [02PZ]
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Proof.
We have already shown that a -Cartier divisor produces a toric line bundle with a toric section. Let now be a toric line bundle equipped with a toric section and the fan that defines . Since every line bundle on an affine toric variety is trivial, for each we can find a section that generates on and such that . Since is regular and nowhere vanishing on and , we can find elements such that , because any regular nowhere vanishing function on a torus is a constant times a monomial. The elements glue together to define a virtual support function on that does not depend on the chosen trivialization. It is easy to see that the correspondence is the inverse of the previous one, which proves the theorem. β