Application of compactness theorem am dle Given an infinite planar graph. If its every finite subgraph is k-colorable, then the graph itself is also k-colorableApplication of compactness theorem Example Given an infinite planar graph. If its every finite subgraph is k-colorable, then the graph itself is also k-colorable. Yi Li (Fudan University) Discrete Mathematics May 9, 2012 4 / 22