Let be such a subdivision. We will construct a canonical formal scheme over associated to together with a morphism which induces the identity on the generic fibre such that there is a one to one correspondence between the open faces of and the strata of . First of all we choose a covering of as in Proposition 2.5. Let be a member of this covering with an Γ©tale morphism and let be the distinguished stratum of . For we set
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and and define
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and . If then is a face of both and by transferring the arguments in [Gub13, Proposition 6.12] to the analytic situation, we obtain that the canonical morphisms are open immersions. Hence we can glue the along this data to obtain a formal scheme which we denote by together with a morphism . Let be the base change of with respect to . The construction of does not depend on the choice of up to isomorphism: Let be another Γ©tale morphism. Then up to reordering the coordinates, for some . Then we have canonical -algebra isomorphisms:
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which yield an isomorphism of the constructed with respectively .
We glue the to obtain our formal scheme . Although might not be admissible, we can define its generic fibre and reduction map in the usual way as the algebras are strictly -affinoid (see [Gub13, Proposition 6.17]). Then induces the identity on the generic fibres and we set . Note that is admissible if the vertices of the polytopes in are -rational, in particular the base change of to the valuation ring of the completion of an algebraic closure of is admissible, see [Gub13, Proposition 6.7].