An edge subdivision is the insertion of a new vertex v_j in the middle of an exiting edge e = v_i v_k accompanied by the joining of the original edge endpoints with the new vertex to form new edges e' = v_i v_j and e'' = v_j v_k. A graph subdivision is therefore a sequence of edge subdivisions. Graphs for which there exists an isomorphism from a subdivision of one to a subdivision of the other are said to be homeomorphic graphs. The opposite of graph subdivision is graph smoothing.