Submission date: 14 October 2011.

Abstract:

We give a new proof of quantifier elimination in the theory of all ordered abelian groups in a suitable language. More precisely, this is only “quantifier elimination relative to ordered sets” in the following sense. Each definable set in the group is a union of a family of quantifier free definable sets, where the parameter of the family runs over a set definable (with quantifiers) in a sort which carries the structure of an ordered set with some additional unary predicates. As a corollary, we find that all definable functions in ordered abelian groups are piecewise affine linear on finitely many definable pieces.

Mathematics Subject Classification: Primary: 06F20, secondary: 03C60, 03C64

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Full text arXiv 1110.3200: pdf, ps.