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  2. Homeomorphism (graph theory) - Wikipedia

    en.wikipedia.org/wiki/Homeomorphism_(graph_theory)

    In general, a subdivision of a graph G (sometimes known as an expansion [2]) is a graph resulting from the subdivision of edges in G. The subdivision of some edge e with endpoints {u,v } yields a graph containing one new vertex w, and with an edge set replacing e by two new edges, {u,w } and {w,v }. For directed edges, this operation shall ...

  3. Subgraph isomorphism problem - Wikipedia

    en.wikipedia.org/wiki/Subgraph_isomorphism_problem

    Subgraph isomorphism is a generalization of the graph isomorphism problem, which asks whether G is isomorphic to H: the answer to the graph isomorphism problem is true if and only if G and H both have the same numbers of vertices and edges and the subgraph isomorphism problem for G and H is true. However the complexity-theoretic status of graph ...

  4. Two-graph - Wikipedia

    en.wikipedia.org/wiki/Two-graph

    Switching {X,Y} in a graph. A two-graph is equivalent to a switching class of graphs and also to a (signed) switching class of signed complete graphs.. Switching a set of vertices in a (simple) graph means reversing the adjacencies of each pair of vertices, one in the set and the other not in the set: thus the edge set is changed so that an adjacent pair becomes nonadjacent and a nonadjacent ...

  5. Graphlets - Wikipedia

    en.wikipedia.org/wiki/Graphlets

    Graphlets in mathematics are induced subgraph isomorphism classes in a graph, [1] [2] i.e. two graphlet occurrences are isomorphic, whereas two graphlets are non-isomorphic. . Graphlets differ from network motifs in a statistical sense, network motifs are defined as over- or under-represented graphlets with respect to some random graph null m

  6. Graph isomorphism problem - Wikipedia

    en.wikipedia.org/wiki/Graph_isomorphism_problem

    Graphs are commonly used to encode structural information in many fields, including computer vision and pattern recognition, and graph matching, i.e., identification of similarities between graphs, is an important tools in these areas. In these areas graph isomorphism problem is known as the exact graph matching. [47]

  7. Glossary of graph theory - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_graph_theory

    The complement graph ¯ of a simple graph G is another graph on the same vertex set as G, with an edge for each two vertices that are not adjacent in G. complete 1. A complete graph is one in which every two vertices are adjacent: all edges that could exist are present. A complete graph with n vertices is often denoted K n.

  8. Graph matching - Wikipedia

    en.wikipedia.org/wiki/Graph_matching

    The case of exact graph matching is known as the graph isomorphism problem. [1] The problem of exact matching of a graph to a part of another graph is called subgraph isomorphism problem. Inexact graph matching refers to matching problems when exact matching is impossible, e.g., when the number of vertices in the two graphs are different. In ...

  9. Graph homomorphism - Wikipedia

    en.wikipedia.org/wiki/Graph_homomorphism

    Two graphs G and H are homomorphically equivalent if G → H and H → G. [4] The maps are not necessarily surjective nor injective. For instance, the complete bipartite graphs K 2,2 and K 3,3 are homomorphically equivalent: each map can be defined as taking the left (resp. right) half of the domain graph and mapping to just one vertex in the left (resp. right) half of the image graph.