David Trotman – On the local geometry of definably stratified sets Carte non disponible Date/heure Date(s) - 16 février 2017 Catégories Pas de Catégories With Guillaume Valette (IMPAN, Cracovie). We prove that a 1985 theorem of Pawlucki, showing that Whitney regularity for a subanalytic set S with a smooth singular locus of codimension one implies that S is a finite union of C1 manifolds with boundary, applies to definable sets in polynomially bounded o-minimal structures. We give a refined version of Pawlucki’s theorem for arbitrary o-minimal structures, replacing Whitney (b)-regularity by a quantified version, and prove related results concerning normal cones and continuity of the density. We analyse two counterexamples to the extension of Pawlucki’s theorem to definable subsets in general o-minimal structures, and to several other statements valid for subanalytic sets.In particular we give the first example of a Whitney (b)-regular definably stratified set for which the density is not continuous along a stratum.[
David Trotman – On the local geometry of definably stratified sets Carte non disponible Date/heure Date(s) - 16 février 2017 Catégories Pas de Catégories With Guillaume Valette (IMPAN, Cracovie). We prove that a 1985 theorem of Pawlucki, showing that Whitney regularity for a subanalytic set S with a smooth singular locus of codimension one implies that S is a finite union of C1 manifolds with boundary, applies to definable sets in polynomially bounded o-minimal structures. We give a refined version of Pawlucki’s theorem for arbitrary o-minimal structures, replacing Whitney (b)-regularity by a quantified version, and prove related results concerning normal cones and continuity of the density. We analyse two counterexamples to the extension of Pawlucki’s theorem to definable subsets in general o-minimal structures, and to several other statements valid for subanalytic sets.In particular we give the first example of a Whitney (b)-regular definably stratified set for which the density is not continuous along a stratum.[