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OverlappingBlockPairs ​

Pairs of blocks A, B with min A < min B < max A < max B.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt000563via SetPartition✓
OverlappingBlockPairs(partition)Pairs of blocks A, B with min A < min B < max A < max B.
Typed signatures
TypePackageApplies
(set_partition) -> numbercombinatoricsalways

Domain: Set partition statistics

Details
  • Defined over SetPartition as an expression in _x, evaluated by compute-engine — the definition IS the implementation.
  • Takes a SetPartition 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.

Definition

Epsil, as the implementation runs it.

on SetPartition, over _x

0 if Length(_x) < 2 else Sum(Map(Function(
                                           Count(Filter(
                                                         Range(
                                                                i + 1,
                                                                Length(_x),
                                                                1,
                                                              ),
                                                         Function(Map(
                                                                       Function(b[1], b),
                                                                       _x,
                                                                     )[j] <
                                                                  Map(
                                                                       Function(Last(b), b),
                                                                       _x,
                                                                     )[i] && Map(
                                                                           Function(Last(b), b),
                                                                           _x,
                                                                         )[i] <
                                                                      Map(
                                                                           Function(Last(b), b),
                                                                           _x,
                                                                         )[j], j),
                                                       )),
                                           i,
                                         ), Range(1, Length(_x))))

Examples

Basic #

the partition {1,3}∣{2}\{1,3\} \mid \{2\}

live ↗
InOverlappingBlockPairs(SetPartition⁡([[1,3],[2]]))\mathrm{OverlappingBlockPairs}({\operatorname{SetPartition}}([[1, 3], [2]]))Out00

the partition {1}∣{2,4}∣{3}\{1\} \mid \{2,4\} \mid \{3\}

live ↗
InOverlappingBlockPairs(SetPartition⁡([[1],[2,4],[3]]))\mathrm{OverlappingBlockPairs}({\operatorname{SetPartition}}([[1], [2, 4], [3]]))Out00
Properties #

FindStat's value for {{1,2}}

live ↗
InCombinatorialStat(SetPartition⁡([[1,2]]),OverlappingBlockPairs)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1, 2]]), \text{OverlappingBlockPairs})Out00

Known value · FindStat St000563

FindStat's value for {{1,2,3}}

live ↗
InCombinatorialStat(SetPartition⁡([[1,2,3]]),OverlappingBlockPairs)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1, 2, 3]]), \text{OverlappingBlockPairs})Out00

Known value · FindStat St000563

FindStat's value for {{1},{2}}

live ↗
InCombinatorialStat(SetPartition⁡([[1],[2]]),OverlappingBlockPairs)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1], [2]]), \text{OverlappingBlockPairs})Out00

Known value · FindStat St000563

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