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MinimumVertexCoverCount ​

The vertex covers with the fewest vertices: the independent sets with the most.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt000363via LabeledGraph✓
MinimumVertexCoverCount(graph)The vertex covers with the fewest vertices: the independent sets with the most.
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 St000363: the covers of the least possible size, which are the complements of the largest independent sets. The graph with no vertices has the empty cover, so 1.

Definition

Epsil, as the implementation runs it.

on LabeledGraph, over _x

1 if _x[1] == 0 else Apply((n: integer) => Apply((edges: list<list<integer>>) => Apply(
                                                                                        (inside: list<integer>) => Apply(
                                                                                                                          (totals: list<integer>) => Apply(
                                                                                                                                                            (top: integer) => Max(Sum(Map(Function((1 if inside[m + 1] ==
                                                                                                                                                                                                         0 else 0) *
                                                                                                                                                                                                   (1 if totals[m + 1] ==
                                                                                                                                                                                                         top else 0), m), Range(0, 2 ^ n -
                                                                                                                                                                                                                  1))), 0),
                                                                                                                                                            Max(Map(Function((1 if inside[m + 1] ==
                                                                                                                                                                                   0 else 0) *
                                                                                                                                                                             totals[m + 1], m), Range(0, 2 ^ n -
                                                                                                                                                                                            1))),
                                                                                                                                                          ),
                                                                                                                          Map(
                                                                                                                               Function(Max(Sum(Map(Function(1 if m %
                                                                                                                                                                  2 ^ v >=
                                                                                                                                                                  2 ^
                                                                                                                                                                  (v - 1) else 0, v), Range(1, n))), 0), m),
                                                                                                                               Range(0, 2 ^ n -
                                                                                                                                        1),
                                                                                                                             ),
                                                                                                                        ),
                                                                                        Map(
                                                                                             Function(Max(Sum(Map(Function((1 if m %
                                                                                                                                 2 ^ e[1] >=
                                                                                                                                 2 ^
                                                                                                                                 (e[1] - 1) else 0) *
                                                                                                                           (1 if m %
                                                                                                                                 2 ^ e[2] >=
                                                                                                                                 2 ^
                                                                                                                                 (e[2] - 1) else 0), e), edges)), 0), m),
                                                                                             Range(0, 2 ^ n -
                                                                                                      1),
                                                                                           ),
                                                                                      ), _x[2]), _x[1])

Examples

Basic #

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

live ↗
InMinimumVertexCoverCount(LabeledGraph⁡((4,[[1,2],[2,3],[2,4],[3,4]])))\mathrm{MinimumVertexCoverCount}(\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)))Out22
Properties #

FindStat's value for ([],1)

live ↗
InCombinatorialStat(LabeledGraph⁡((1,[])),MinimumVertexCoverCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((1,\bigl\lbrack\bigr\rbrack)), \text{MinimumVertexCoverCount})Out11

Known value · FindStat St000363

FindStat's value for ([],2)

live ↗
InCombinatorialStat(LabeledGraph⁡((2,[])),MinimumVertexCoverCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((2,\bigl\lbrack\bigr\rbrack)), \text{MinimumVertexCoverCount})Out11

Known value · FindStat St000363

FindStat's value for ([],3)

live ↗
InCombinatorialStat(LabeledGraph⁡((3,[])),MinimumVertexCoverCount)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((3,\bigl\lbrack\bigr\rbrack)), \text{MinimumVertexCoverCount})Out11

Known value · FindStat St000363

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