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MatchingNumber ​

The most edges with no two sharing a vertex.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt000387via LabeledGraph✓
MatchingNumber(graph)The most edges with no two sharing a vertex.
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 St000387. 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(
                                                                                                                                                            (adjacency: list<list<integer>>) => Apply((a_init: list<integer>) => Fold((a: list<integer>, b) => Apply(
                                                                                                                                                                                                                                                                      (a_next: list<integer>) => a_next,
                                                                                                                                                                                                                                                                      Apply(
                                                                                                                                                                                                                                                                             (low: integer) => Join(a, [Max(a[b -
                                                                                                                                                                                                                                                                                                              2 ^
                                                                                                                                                                                                                                                                                                              (low - 1) +
                                                                                                                                                                                                                                                                                                              1], Max(Map(Function(adjacency[low][w] *
                                                                                                                                                                                                                                                                                                                                  (a[b -
                                                                                                                                                                                                                                                                                                                                     2 ^
                                                                                                                                                                                                                                                                                                                                     (low - 1) -
                                                                                                                                                                                                                                                                                                                                     2 ^
                                                                                                                                                                                                                                                                                                                                     (w - 1) +
                                                                                                                                                                                                                                                                                                                                     1] +
                                                                                                                                                                                                                                                                                                                                   1) if (b -
                                                                                                                                                                                                                                                                                                                                       2 ^
                                                                                                                                                                                                                                                                                                                                       (low - 1)) %
                                                                                                                                                                                                                                                                                                                                      2 ^ w >=
                                                                                                                                                                                                                                                                                                                                      2 ^
                                                                                                                                                                                                                                                                                                                                      (w - 1) else 0, w), Range(1, n))))]),
                                                                                                                                                                                                                                                                             Min(Map(Function(v if b %
                                                                                                                                                                                                                                                                                                   2 ^ v >=
                                                                                                                                                                                                                                                                                                   2 ^
                                                                                                                                                                                                                                                                                                   (v - 1) else n + 1, v), Range(1, n))),
                                                                                                                                                                                                                                                                           ),
                                                                                                                                                                                                                                                                    ), a_init, Range(1, 2 ^ n -
                                                                                                                                                                                                                                                                                       1)), [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),
                                                                                                                                                               ),
                                                                                                                                                          )[Length(Apply(
                                                                                                                                                                         (adjacency: list<list<integer>>) => Apply((a_init: list<integer>) => Fold((a: list<integer>, b) => Apply(
                                                                                                                                                                                                                                                                                   (a_next: list<integer>) => a_next,
                                                                                                                                                                                                                                                                                   Apply(
                                                                                                                                                                                                                                                                                          (low: integer) => Join(a, [Max(a[b -
                                                                                                                                                                                                                                                                                                                           2 ^
                                                                                                                                                                                                                                                                                                                           (low - 1) +
                                                                                                                                                                                                                                                                                                                           1], Max(Map(Function(adjacency[low][w] *
                                                                                                                                                                                                                                                                                                                                               (a[b -
                                                                                                                                                                                                                                                                                                                                                  2 ^
                                                                                                                                                                                                                                                                                                                                                  (low - 1) -
                                                                                                                                                                                                                                                                                                                                                  2 ^
                                                                                                                                                                                                                                                                                                                                                  (w - 1) +
                                                                                                                                                                                                                                                                                                                                                  1] +
                                                                                                                                                                                                                                                                                                                                                1) if (b -
                                                                                                                                                                                                                                                                                                                                                    2 ^
                                                                                                                                                                                                                                                                                                                                                    (low - 1)) %
                                                                                                                                                                                                                                                                                                                                                   2 ^ w >=
                                                                                                                                                                                                                                                                                                                                                   2 ^
                                                                                                                                                                                                                                                                                                                                                   (w - 1) else 0, w), Range(1, n))))]),
                                                                                                                                                                                                                                                                                          Min(Map(Function(v if b %
                                                                                                                                                                                                                                                                                                                2 ^ v >=
                                                                                                                                                                                                                                                                                                                2 ^
                                                                                                                                                                                                                                                                                                                (v - 1) else n + 1, v), Range(1, n))),
                                                                                                                                                                                                                                                                                        ),
                                                                                                                                                                                                                                                                                 ), a_init, Range(1, 2 ^ n -
                                                                                                                                                                                                                                                                                                    1)), [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),
                                                                                                                                                                            ),
                                                                                                                                                                       ))],
                                                                                                                          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 ↗
InMatchingNumber(LabeledGraph⁡((4,[[1,2],[2,3],[2,4],[3,4]])))\mathrm{MatchingNumber}(\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,[])),MatchingNumber)\mathrm{CombinatorialStat}(\operatorname{LabeledGraph}((1,\bigl\lbrack\bigr\rbrack)), \text{MatchingNumber})Out00

Known value · FindStat St000387

FindStat's value for ([],2)

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

Known value · FindStat St000387

FindStat's value for ([],3)

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

Known value · FindStat St000387

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Examples4
CrosswalkFindStat