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TerminalClosers ​

Closers e with every larger element also a closer.

✓ checked against that system · ! checked, with disagreements (hover a chip)FindStatSt001050via SetPartition✓
TerminalClosers(partition)Closers e with every larger element also a closer.
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.

Examples

Basic #

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

live ↗
InTerminalClosers(SetPartition⁡([[1,3],[2]]))\mathrm{TerminalClosers}({\operatorname{SetPartition}}([[1, 3], [2]]))Out22

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

live ↗
InTerminalClosers(SetPartition⁡([[1],[2,4],[3]]))\mathrm{TerminalClosers}({\operatorname{SetPartition}}([[1], [2, 4], [3]]))Out22
Properties #

FindStat's value for {{1}}

live ↗
InCombinatorialStat(SetPartition⁡([[1]]),TerminalClosers)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1]]), \text{TerminalClosers})Out11

Known value · FindStat St001050

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

live ↗
InCombinatorialStat(SetPartition⁡([[1,2]]),TerminalClosers)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1, 2]]), \text{TerminalClosers})Out11

Known value · FindStat St001050

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

live ↗
InCombinatorialStat(SetPartition⁡([[1,2,3]]),TerminalClosers)\mathrm{CombinatorialStat}({\operatorname{SetPartition}}([[1, 2, 3]]), \text{TerminalClosers})Out11

Known value · FindStat St001050

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