***************************************************************************** * www.FindStat.org - The Combinatorial Statistic Finder * * * * Copyright (C) 2019 The FindStatCrew * * * * This information is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * ***************************************************************************** ----------------------------------------------------------------------------- Statistic identifier: St001572 ----------------------------------------------------------------------------- Collection: Graphs ----------------------------------------------------------------------------- Description: The minimal number of edges to remove to make a graph bipartite. ----------------------------------------------------------------------------- References: ----------------------------------------------------------------------------- Code: @cached_function def graph_of_graphs(n): """ sage: H = graph_of_graphs(4) sage: H.relabel(lambda g: tuple(g.edges(labels=False))) sage: H.show() """ lg1 = [(i, g.canonical_label().copy(immutable=True)) for i, g in enumerate(graphs(n))] lg2 = {g: i for i, g in lg1} lg1 = dict(lg1) H = Graph(len(lg1)) for g in lg2: h = g.copy(immutable=False) for e in g.edges(labels=False): h.delete_edge(e) g2 = h.copy().canonical_label().copy(immutable=true) H.add_edge([lg2[g], lg2[g2]]) h.add_edge(e) H.relabel(lambda i: lg1[i]) return H def statistic(g): mn = g.num_verts() G = graph_of_graphs(g.num_verts()) g = g.canonical_label().copy(immutable=True) for h in G.vertices(sort=False): if h.is_bipartite(): mn = min(mn, G.shortest_path_length(g, h)) if mn == 0: return mn return mn ----------------------------------------------------------------------------- Statistic values: ([],1) => 0 ([],2) => 0 ([(0,1)],2) => 0 ([],3) => 0 ([(1,2)],3) => 0 ([(0,2),(1,2)],3) => 0 ([(0,1),(0,2),(1,2)],3) => 1 ([],4) => 0 ([(2,3)],4) => 0 ([(1,3),(2,3)],4) => 0 ([(0,3),(1,3),(2,3)],4) => 0 ([(0,3),(1,2)],4) => 0 ([(0,3),(1,2),(2,3)],4) => 0 ([(1,2),(1,3),(2,3)],4) => 1 ([(0,3),(1,2),(1,3),(2,3)],4) => 1 ([(0,2),(0,3),(1,2),(1,3)],4) => 0 ([(0,2),(0,3),(1,2),(1,3),(2,3)],4) => 1 ([(0,1),(0,2),(0,3),(1,2),(1,3),(2,3)],4) => 2 ([],5) => 0 ([(3,4)],5) => 0 ([(2,4),(3,4)],5) => 0 ([(1,4),(2,4),(3,4)],5) => 0 ([(0,4),(1,4),(2,4),(3,4)],5) => 0 ([(1,4),(2,3)],5) => 0 ([(1,4),(2,3),(3,4)],5) => 0 ([(0,1),(2,4),(3,4)],5) => 0 ([(2,3),(2,4),(3,4)],5) => 1 ([(0,4),(1,4),(2,3),(3,4)],5) => 0 ([(1,4),(2,3),(2,4),(3,4)],5) => 1 ([(0,4),(1,4),(2,3),(2,4),(3,4)],5) => 1 ([(1,3),(1,4),(2,3),(2,4)],5) => 0 ([(0,4),(1,2),(1,3),(2,4),(3,4)],5) => 0 ([(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 1 ([(0,4),(1,3),(2,3),(2,4),(3,4)],5) => 1 ([(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 1 ([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4)],5) => 0 ([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 1 ([(0,4),(1,3),(2,3),(2,4)],5) => 0 ([(0,1),(2,3),(2,4),(3,4)],5) => 1 ([(0,3),(1,2),(1,4),(2,4),(3,4)],5) => 1 ([(0,3),(0,4),(1,2),(1,4),(2,4),(3,4)],5) => 2 ([(0,3),(0,4),(1,2),(1,4),(2,3)],5) => 1 ([(0,1),(0,4),(1,3),(2,3),(2,4),(3,4)],5) => 1 ([(0,3),(0,4),(1,2),(1,4),(2,3),(2,4),(3,4)],5) => 2 ([(0,4),(1,2),(1,3),(2,3),(2,4),(3,4)],5) => 1 ([(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2 ([(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2 ([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2 ([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4)],5) => 1 ([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,4),(3,4)],5) => 2 ([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 3 ([(0,1),(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 4 ([],6) => 0 ([(4,5)],6) => 0 ([(3,5),(4,5)],6) => 0 ([(2,5),(3,5),(4,5)],6) => 0 ([(1,5),(2,5),(3,5),(4,5)],6) => 0 ([(0,5),(1,5),(2,5),(3,5),(4,5)],6) => 0 ([(2,5),(3,4)],6) => 0 ([(2,5),(3,4),(4,5)],6) => 0 ([(1,2),(3,5),(4,5)],6) => 0 ([(3,4),(3,5),(4,5)],6) => 1 ([(1,5),(2,5),(3,4),(4,5)],6) => 0 ([(0,1),(2,5),(3,5),(4,5)],6) => 0 ([(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,5),(2,5),(3,4),(4,5)],6) => 0 ([(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,5),(1,5),(2,4),(3,4)],6) => 0 ([(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 0 ([(0,5),(1,5),(2,3),(3,4),(4,5)],6) => 0 ([(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,5),(2,4),(3,4),(4,5)],6) => 0 ([(0,5),(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 0 ([(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(2,3)],6) => 0 ([(1,5),(2,4),(3,4),(3,5)],6) => 0 ([(0,1),(2,5),(3,4),(4,5)],6) => 0 ([(1,2),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(2,3),(3,5),(4,5)],6) => 0 ([(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 1 ([(0,1),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 1 ([(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2 ([(1,4),(1,5),(2,3),(2,5),(3,4)],6) => 1 ([(0,5),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 0 ([(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,2),(1,4),(2,3),(3,5),(4,5)],6) => 1 ([(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(2,3),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(2,3),(2,4),(3,5)],6) => 0 ([(0,1),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,5),(1,5),(2,3),(2,4),(3,4)],6) => 1 ([(0,4),(1,2),(1,3),(2,5),(3,5),(4,5)],6) => 0 ([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5)],6) => 1 ([(0,4),(1,2),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,1),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 1 ([(0,3),(0,4),(1,2),(1,5),(2,5),(3,5),(4,5)],6) => 1 ([(0,3),(1,4),(1,5),(2,4),(2,5),(3,5),(4,5)],6) => 1 ([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,3),(0,5),(1,3),(1,5),(2,4),(2,5),(3,4),(4,5)],6) => 1 ([(0,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 0 ([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 1 ([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2 ([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(2,5),(3,4)],6) => 0 ([(0,3),(0,5),(1,2),(1,5),(2,4),(3,4),(4,5)],6) => 0 ([(0,5),(1,2),(1,4),(2,3),(3,4),(3,5),(4,5)],6) => 1 ([(0,1),(0,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1 ([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,5),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,1),(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(2,4),(2,5),(3,4),(3,5)],6) => 0 ([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 1 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 1 ([(0,4),(0,5),(1,2),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,2),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,2),(1,4),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5)],6) => 0 ([(0,1),(0,2),(0,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1 ([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,2),(1,3),(2,3),(4,5)],6) => 2 ([(0,2),(1,4),(1,5),(2,3),(3,4),(3,5),(4,5)],6) => 1 ([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(4,5)],6) => 2 ([(0,1),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,2),(1,3),(2,3),(2,5),(3,4),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 2 ([(0,3),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,3),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4)],6) => 1 ([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2 ([(0,3),(0,4),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 3 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,4)],6) => 2 ([(0,1),(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 3 ([(0,1),(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,2),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3 ([(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 3 ([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 3 ([(0,1),(0,4),(0,5),(1,2),(1,3),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2 ([(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 3 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 4 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 4 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 5 ([(0,1),(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 6 ----------------------------------------------------------------------------- Created: Jul 23, 2020 at 12:52 by Martin Rubey ----------------------------------------------------------------------------- Last Updated: Dec 23, 2020 at 11:54 by Martin Rubey