Strong chromatic index of graphs: a short survey

A strong edge coloring of a graph G is an edge coloring such that every two adjacent edges or two edges adjacent to a same edge receive two distinct colors; in other words, every path of length three has three distinct colors in G. 

The strong chromatic index of G, denoted by X's (G) , is the smallest integer k such that G admits a strong edge coloring with k colors. This survey is an brief introduction to some good results regarding the strong chromatic index of planar graphs, bipartite graphs and so on.