Example 4.109 . [02SS]
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Example 4.109.
Let be a complete fan in and a support function on . By Theorem 4.97, any equivalence class of semipositive models of is determined by a rational piecewise affine concave function with . By Lemma 3.79, any such function can be realized as the inverse image by an affine map of the support function of a standard simplex. Using the previous proposition, any equivalence class of semipositive toric models can be induced by an equivariant projective morphism.
More explicitly, let be an integer such that is an H-lattice concave function. Let be a complete SCR complex in compatible by and such that (see the proof of Theorem 4.97). Then, is a toric model of in the class determined by .
Choose an H-representation with for . Put . Let and be as in Lemma 3.79. In our case, is a morphism of lattices and
| (4.110) |
We follow examples 4.3, 4.26, 4.44 and 4.75, and consider as a toric scheme over . Let be a rational point in the principal open subset of such that . One can verify that the hypothesis of Proposition 4.72 are satisfied. Let be the associated morphism. Then