English

Model-completion of scaled lattices

Logic 2016-08-16 v1

Abstract

It is known from Grzegorczyk's paper \cite{grze-1951} that the lattice of real semi-algebraic closed subsets of Rn{\mathbb R}^n is undecidable for every integer n2n\geq 2. More generally, if XX is any definable set over a real or algebraically closed field KK, then the lattice L(X)L(X) of all definable subsets of XX closed in XX is undecidable whenever dimX2\dim X\geq 2. Nevertheless, we investigate in this paper the model theory of the class SC_def(K,d){\rm SC\_{def}}(K,d) of all such lattices L(X)L(X) with dimXd\dim X\leq d and KK as above or a henselian valued field of characteristic zero. <p> We show that the universal theory of SC_def(K,d){\rm SC\_{def}}(K,d), in a natural expansion by definition of the lattice language, is the same for every such field KK. We give a finite axiomatization of it and prove that it is locally finite and admits a model-completion, which turns to be decidable as well as all its completions. We expect L(Q_pd)L({\mathbb Q}\_p^d) to be a model of (a little variant of) this model-completion. This leads us to a new conjecture in pp-adic semi-algebraic geometry which, combined with the results of this paper, would give decidability (via a natural recursive axiomatization) and elimination of quantifiers for the complete theory of L(R_pd)L({\mathbb R}\_p^d), uniformly in pp.

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Cite

@article{arxiv.math/0606792,
  title  = {Model-completion of scaled lattices},
  author = {Luck Darnière},
  journal= {arXiv preprint arXiv:math/0606792},
  year   = {2016}
}

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27 pages