7.4 [037G]
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7.4
We consider now a compact analytic space over of pure dimension . Theorem 7.3 shows that the tropical variety is the support of an integral -affine polytopal complex in . Our next goal is to endow this complex with canonical tropical multiplicities. This will lead to the definition of a weighted polytopal complex which is canonical up to subdivision.
If , then we set meaning that we choose all tropical weights equal to zero. It remains to consider the case . As seen in Example 4.5, we may identify with the skeleton of . We choose a generic surjective homomorphism onto a split multiplicative torus of rank . Generic means that the corresponding linear map is injective on every polytope contained in . By Theorem 7.3, there is an integral -affine polytopal complex in with such that is disjoint from for every -dimensional face of and . By passing to a subdivision, we may assume that is a polyhedral complex in as in 3.9.
We identify with a subset of the skeleton as in Remark 4.5. Then it is clear that restricts to a map which agrees with on using the identification . It is shown in [CD12], §2.4, that is a finite flat and surjective morphism which means that every point of has a neighbourhood in such that has these properties. Since is connected, the corresponding degree depends only on and not on the choice of . We denote this degree by .
Recall that is the canonical lattice in the affine space generated by . Then the character lattice of is of finite index in .