Date(s) - 30/06/2016
14 h 00 min - 15 h 00 min
Catégories Pas de Catégories
In this talk we will present some criteria of tangent cones so that a definable set is a $C^1$ manifold. Namely, let $X$ be a connected locally closed definable set in $R^n$, we show that the following statements are equivalent
1) $X$ is a $C^1$ manifold
2) Tangent cone and paratangent cone of $X$ coincide,
3) The tangent cone $T_x X$ of $X$ at the point $x$ is k-dimensional linear subspace of $R^n$ (k does not depend on $x$) varies continuously in $x$, and the density $\theta(X, x) < 3/2$.