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TriangleVertexCount ​

The vertices on a triangle.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt001995via LabeledGraph✓
TriangleVertexCount(graph)The vertices on a triangle.
Typed signatures
TypePackageApplies
(labeled_graph) -> numbercombinatoricsalways

Domain: Graph statistics

Details
  • Defined over LabeledGraph as an expression in _x, evaluated by compute-engine — the definition IS the implementation.
  • Takes a LabeledGraph and nothing else — it reads values against their positions, or walks the orbits, so it needs the bijection. Applying it to a bare list is a type error, not a wrong answer.
  • FindStat's St001995. A vertex lies on a triangle when it is adjacent to both ends of some edge. The graph with no vertices gives 0.

Definition

Epsil, as the implementation runs it.

on LabeledGraph, over _x

0 if _x[1] == 0 else Apply((n: integer) => Apply((edges: list<list<integer>>) => Apply(
                                                                                        (adjacency: list<list<integer>>) => Max(Sum(Map(Function(1 if Max(Sum(Map(Function(adjacency[v][e[1]] * adjacency[v][e[2]], e), edges)), 0) >
                                                                                                                                                      0 else 0, v), Range(1, n))), 0),
                                                                                        Map(Function(Map(
                                                                                                          Function(Max(Sum(Map(Function((1 if e[1] == i else 0) *
                                                                                                                                        (1 if e[2] == j else 0) +
                                                                                                                                        (1 if e[1] == j else 0) *
                                                                                                                                        (1 if e[2] == i else 0), e), edges)), 0), j),
                                                                                                          Range(1, n),
                                                                                                        ), i), Range(1, n)),
                                                                                      ), _x[2]), _x[1])

Examples

Basic #

the graph on 4 vertices with the edges 12, 23, 24 and 34

live ↗
InTriangleVertexCount(LabeledGraph⁡((4,[[1,2],[2,3],[2,4],[3,4]])))\mathrm{TriangleVertexCount}(\operatorname{LabeledGraph}((4,\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack2, 3\bigr\rbrack, \bigl\lbrack2, 4\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack)))Out33
Properties #

FindStat's value for ([],1)

live ↗
InCombinatorialStat(LabeledGraph⁡((1,[])),TriangleVertexCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((1,\bigl\lbrack\bigr\rbrack)), \text{TriangleVertexCount})Out00

Known value · FindStat St001995

FindStat's value for ([],2)

live ↗
InCombinatorialStat(LabeledGraph⁡((2,[])),TriangleVertexCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((2,\bigl\lbrack\bigr\rbrack)), \text{TriangleVertexCount})Out00

Known value · FindStat St001995

FindStat's value for ([],3)

live ↗
InCombinatorialStat(LabeledGraph⁡((3,[])),TriangleVertexCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((3,\bigl\lbrack\bigr\rbrack)), \text{TriangleVertexCount})Out00

Known value · FindStat St001995

About
Examples4
CrosswalkFindStat