A quasianalytic class with weakly smooth germs
R. Guénet
TL;DR
The paper constructs an o-minimal expansion of the real field using weakly $C^ olinebreak[4]efty$ germs encoded by a function $H$ with a weakly $C^ olinebreak[4]efty$ germ that is not $C^ olinebreak[4]efty$. It develops a local-to-global framework based on $H$-basic sets, simple sub-$ ext{Λ}$-sets, and monomialization, culminating in a Fiber Cutting program that connects local parametrizations to a global Gabrielov-type complement result. The main contributions are the local simple-$ ext{Λ}$-set decomposition, the constant-rank parametrizations via $H$-manifolds, and the Local/Global Fiber Cutting Lemmas, which together establish model-completeness and o-minimality of $R_H$ without $C^ olinebreak[4]efty$-cell decomposition. This work provides a robust framework for o-minimality in quasianalytic and weakly smooth settings and points toward broader quantifier-elimination results under weaker hypotheses, with potential applications to generalized quasianalytic classes of weakly $C^ olinebreak[4]efty$ germs.
Abstract
In [O. Le Gal, J.-P. Rolin. An o-minimal structure which does not admit $C^\infty$ cellular decomposition. In: Ann. Inst. Fourier 59 (2009), pp 543-562], the authors construct an o-minimal structure which does not admit smooth cell-decomposition. We explain in an appendix that their proof of o-minimality is incomplete and we give a complete proof in the main text.
