Edge-connectivity of graphs with non-negative Bakry–Émery curvature and amply regular graphs

Abstract

We establish a sharp edge-connectivity estimate for graphs with non-negative Bakry–Émery curvature. This leads to a geometric criterion for the existence of a perfect matching. Precisely, we show that any regular graph with non-negative Bakry–Émery curvature and an even or infinite number of vertices has a perfect matching. Through a synthesis of combinatorial and curvature-related techniques, we determine the edge-connectivity of (possibly infinite) amply regular graphs.