3. Edge colorings Definition 49: An proper edge coloring of a graph g is an assignment of colors to the edges of G, one color to each edge, such that adjacent edges receive different colors. An edge coloring in which k colors are used is a k-edge coloring. a graph g is k-edge colorable if there exists an s-edge coloring of G for some ss k. The minimum integer k for which G is k-edge colorable is called the edge chromaticumber or the chromatic index x'(G) of G. If x' (G)=k, then g is k-edge chromatic▪ 3. Edge colorings ▪ Definition 49:An proper edge coloring of a graph G is an assignment of colors to the edges of G, one color to each edge, such that adjacent edges receive different colors. An edge coloring in which k colors are used is a k-edge coloring. A graph G is k-edge colorable if there exists an s-edge coloring of G for some s k. The minimum integer k for which G is k-edge colorable is called the edge chromaticumber or the chromatic index ’(G) of G. If ’(G) = k, then G is k-edge chromatic