**Speaker**: Liping Yuan (苑立平), Hebei Normal University

**Date**: Thu, Dec 07, 2017

**Time**: 10:30 - 11:30

**Venue**: Middle Meeting Room

**Title**: On $\cal F$-convexity

**Abstract**:

Let $\cal F$ be a family of sets in $R^d$. A set $M \subset R^d$ is called $\cal F$-convex if for every pair of distinct points $x,y\in M$ there is a set $F\in \cal F$ such that $x,y\in F$ and $F\subset M$. In this talk we'll present some properties of some $\cal F$- convex sets.