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networks[contract] - contracts edges in a graph
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Calling Sequence
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contract(Eset, G)
contract(Pset, G)
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Parameters
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G
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graph or network
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Eset
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edge or set or list of edges of G
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Pset
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connected vertex pair or a set or list of connected vertex pairs
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Description
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This procedure contracts the edges of G, specified by the first argument.
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The edges to be contracted may be specified either individually or as a set of edge names or pairs of ends of edges (for example, {1,3} ).
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If pairs of ends are used, each pair must uniquely identify an edge.
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This procedure returns as its value the name of the vertex that survived the contraction of the specified edge. If more than one edge is contracted, then a set of surviving names is provided.
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This routine is normally loaded by using the command with(networks), but it may also be referenced by using the full name networks[contract](...).
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Examples
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Important: The networks package has been deprecated. Use the superseding command GraphTheory[Contract] instead.
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| (1) |
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map(proc(e,G) [ e, ends(e,G) ] end proc, edges(G), G);
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![{[e1, {1, 2}], [e2, {1, 3}], [e4, {2, 3}], [e5, {1, 2}], [e6, {1, 3}]}](/support/helpjp/helpview.aspx?si=8200/file07392/math126.png)
| (2) |
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![e := addedge([v, 3], G)](/support/helpjp/helpview.aspx?si=8200/file07392/math130.png)
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| (3) |
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![contract([v, 3], G)](/support/helpjp/helpview.aspx?si=8200/file07392/math137.png)
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| (4) |
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map(proc(e,G) [ e, ends(e,G) ] end proc, edges(G), G);
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![{[e1, {1, 2}], [e2, {1}], [e4, {1, 2}], [e5, {1, 2}], [e6, {1}]}](/support/helpjp/helpview.aspx?si=8200/file07392/math147.png)
| (5) |
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