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GraphPackingNumber ​

The most vertices, no two within distance 2: the closed neighborhoods of the vertices are disjoint.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt000916via LabeledGraph✓
GraphPackingNumber(graph)The most vertices, no two within distance 2: the closed neighborhoods of the vertices are disjoint.
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 St000916. A set is a packing when every vertex has at most one member among itself and its neighbors. 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(
                                                                                        (inside: list<integer>) => Apply(
                                                                                                                          (totals: list<integer>) => Apply(
                                                                                                                                                            (toSet: list<list<integer>>) => Max(Map(Function((1 if Max(Sum(Map(Function(1 if toSet[m + 1][w] +
                                                                                                                                                                                                                                             (1 if m %
                                                                                                                                                                                                                                                   2 ^ w >=
                                                                                                                                                                                                                                                   2 ^
                                                                                                                                                                                                                                                   (w - 1) else 0) >
                                                                                                                                                                                                                                             1 else 0, w), Range(1, n))), 0) ==
                                                                                                                                                                                                                   0 else 0) *
                                                                                                                                                                                                             totals[m + 1], m), Range(0, 2 ^ n -
                                                                                                                                                                                                                            1))),
                                                                                                                                                            Map(
                                                                                                                                                                 Function(Map(Function(Max(Sum(Map(Function((1 if e[1] == v else 0) *
                                                                                                                                                                                                            (1 if m %
                                                                                                                                                                                                                  2 ^ e[2] >=
                                                                                                                                                                                                                  2 ^
                                                                                                                                                                                                                  (e[2] - 1) else 0) +
                                                                                                                                                                                                            (1 if e[2] == v else 0) *
                                                                                                                                                                                                            (1 if m %
                                                                                                                                                                                                                  2 ^ e[1] >=
                                                                                                                                                                                                                  2 ^
                                                                                                                                                                                                                  (e[1] - 1) else 0), e), edges)), 0), v), Range(1, n)), 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 ↗
InGraphPackingNumber(LabeledGraph⁡((4,[[1,2],[2,3],[2,4],[3,4]])))\mathrm{GraphPackingNumber}(\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)))Out11
Properties #

FindStat's value for ([],1)

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

Known value · FindStat St000916

FindStat's value for ([],2)

live ↗
InCombinatorialStat(LabeledGraph⁡((2,[])),GraphPackingNumber)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((2,\bigl\lbrack\bigr\rbrack)), \text{GraphPackingNumber})Out22

Known value · FindStat St000916

FindStat's value for ([],3)

live ↗
InCombinatorialStat(LabeledGraph⁡((3,[])),GraphPackingNumber)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((3,\bigl\lbrack\bigr\rbrack)), \text{GraphPackingNumber})Out33

Known value · FindStat St000916

About
Examples4
CrosswalkFindStat