**Speaker**: Bobo Hua (华波波), Fudan University

**Date**: Fri, Apr 28, 2017

**Time**: 16:30 - 17:30

**Venue**: Room 3323

**Title**: Combinatorial curvature for planar graphs

**Abstract**:

The combinatorial curvature of a planar graph is defined as the generalized Gaussian curvature of its polygonal surface with a piecewise flat metric. We will show that the total curvature of a planar graph with nonnegative combinatorial curvature, whose faces are isometric to Euclidean regular polygons, is an integral multiple of $1/12$, up to a normalization of $2\pi$.

This is joint work with Yanhui Su.