GraphTheory
ContractSubgraph
contract subgraph to single vertex
Calling Sequence
Parameters
Description
Examples
Compatibility
ContractSubgraph(G, S)
G
-
graph
S
set or list of vertices, or a subgraph of G
The ContractSubgraph command returns a new graph with all the vertices in S merged into a single vertex. The neighborhood of the new vertex will be the union of the neighborhoods of all of merged vertices.
If S is given as a subgraph of G, all the vertices of S will be contracted.
To contract a single edge, use the Contract command.
with⁡GraphTheory:
C6 ≔ CycleGraph⁡6
C6≔Graph 1: an undirected graph with 6 vertices and 6 edge(s)
H ≔ ContractSubgraph⁡C6,1,2,6
H≔Graph 2: an undirected graph with 4 vertices and 4 edge(s)
Vertices⁡H
1,3,4,5
Edges⁡H
1,3,1,5,3,4,4,5
with⁡SpecialGraphs:
P ≔ PetersenGraph⁡
P≔Graph 3: an undirected graph with 10 vertices and 15 edge(s)
DrawGraph⁡P
H ≔ ContractSubgraph⁡P,1,2,3,6,7,9
H≔Graph 4: an undirected graph with 5 vertices and 7 edge(s)
DrawGraph⁡H
The GraphTheory[ContractSubgraph] command was introduced in Maple 2020.
For more information on Maple 2020 changes, see Updates in Maple 2020.
See Also
DeleteVertex
Subgraph
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