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    Generic derivations on o-minimal structures

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    Let TT be a complete, model complete o-minimal theory extending the theory RCF of real closed ordered fields in some appropriate language LL. We study derivations δ\delta on models M⊨T\mathcal{M}\models T. We introduce the notion of a TT-derivation: a derivation which is compatible with the L(∅)L(\emptyset)-definable C1\mathcal{C}^1-functions on M\mathcal{M}. We show that the theory of TT-models with a TT-derivation has a model completion TGδT^\delta_G. The derivation in models (M,δ)⊨TGδ(\mathcal{M},\delta)\models T^\delta_G behaves "generically," it is wildly discontinuous and its kernel is a dense elementary LL-substructure of M\mathcal{M}. If T=T = RCF, then TGδT^\delta_G is the theory of closed ordered differential fields (CODF) as introduced by Michael Singer. We are able to recover many of the known facts about CODF in our setting. Among other things, we show that TGδT^\delta_G has TT as its open core, that TGδT^\delta_G is distal, and that TGδT^\delta_G eliminates imaginaries. We also show that the theory of TT-models with finitely many commuting TT-derivations has a model completion.Comment: 29 page
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