In graph theory and computer science, the graph sandwich problem is a problem of finding a graph that belongs to a particular family of graphs and is "sandwiched" between two other graphs, one of which must be a subgraph and the other of which must be a supergraph of the desired graph. Graph sandwich problems generalize the problem of testing whether a given graph belongs to a family of graphs, and have attracted attention because of their applications and as a natural generalization of recognition problems.[1]
More precisely, given a vertex set V, a mandatory edge set E1,
and a larger edge set E2,
a graph G = (V, E) is called a sandwich graph for the pair
G1 = (V, E1), G2 = (V, E2) if
E1 ⊆ E ⊆ E2.
The graph sandwich problem for property Π is defined as follows:Cite error: Closing </ref>
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tag It can be solved in polynomial time for split graphs,[2][3] threshold graphs,[2][3] and graphs in which every five vertices contain at most one four-vertex induced path.[4]
The complexity status has also been settled for the H-free graph sandwich problems
for each of the four-vertex graphs H.[5]
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Original source: https://en.wikipedia.org/wiki/Graph sandwich problem.
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