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Nauty :: newEdges

newEdges -- replaces disjoint pairs of edges by disjoint pairs of two-chains

Synopsis

Description

The list of "new edge" graphs are formed as follows: Let ab and cd be disjoint edges of G. Then the associated "new edge" graph H is G with the edges ab and cd removed, the vertices e and f added, and the new edges ae, be, cf, df, and ef added.

i1 : R = QQ[a..d];
i2 : G = graph {a*b, c*d};
i3 : S = QQ[a..f];
i4 : newEdges(G, S)

o4 = {Graph{edges => {{a, e}, {b, e}, {c, f}, {d, f}, {e, f}}}}
            ring => S
            vertices => {a, b, c, d, e, f}

o4 : List

If the List input format is used, then one should use care as the list may contain isomorphic pairs.

Ways to use newEdges :