Identifier
Values
[] => 1
[1] => 1
[2] => 2
[1,1] => 1
[3] => 3
[2,1] => 2
[1,1,1] => 1
[4] => 5
[3,1] => 3
[2,2] => 3
[2,1,1] => 2
[1,1,1,1] => 1
[5] => 7
[4,1] => 5
[3,2] => 5
[3,1,1] => 3
[2,2,1] => 3
[2,1,1,1] => 2
[1,1,1,1,1] => 1
[6] => 11
[5,1] => 7
[4,2] => 8
[4,1,1] => 5
[3,3] => 6
[3,2,1] => 5
[3,1,1,1] => 3
[2,2,2] => 4
[2,2,1,1] => 3
[2,1,1,1,1] => 2
[1,1,1,1,1,1] => 1
[7] => 15
[6,1] => 11
[5,2] => 11
[5,1,1] => 7
[4,3] => 11
[4,2,1] => 8
[4,1,1,1] => 5
[3,3,1] => 6
[3,2,2] => 7
[3,2,1,1] => 5
[3,1,1,1,1] => 3
[2,2,2,1] => 4
[2,2,1,1,1] => 3
[2,1,1,1,1,1] => 2
[1,1,1,1,1,1,1] => 1
[8] => 22
[7,1] => 15
[6,2] => 17
[6,1,1] => 11
[5,3] => 15
[5,2,1] => 11
[5,1,1,1] => 7
[4,4] => 14
[4,3,1] => 11
[4,2,2] => 11
[4,2,1,1] => 8
[4,1,1,1,1] => 5
[3,3,2] => 9
[3,3,1,1] => 6
[3,2,2,1] => 7
[3,2,1,1,1] => 5
[3,1,1,1,1,1] => 3
[2,2,2,2] => 5
[2,2,2,1,1] => 4
[2,2,1,1,1,1] => 3
[2,1,1,1,1,1,1] => 2
[1,1,1,1,1,1,1,1] => 1
[9] => 30
[8,1] => 22
[7,2] => 23
[7,1,1] => 15
[6,3] => 23
[6,2,1] => 17
[6,1,1,1] => 11
[5,4] => 22
[5,3,1] => 15
[5,2,2] => 15
[5,2,1,1] => 11
[5,1,1,1,1] => 7
[4,4,1] => 14
[4,3,2] => 16
[4,3,1,1] => 11
[4,2,2,1] => 11
[4,2,1,1,1] => 8
[4,1,1,1,1,1] => 5
[3,3,3] => 10
[3,3,2,1] => 9
[3,3,1,1,1] => 6
[3,2,2,2] => 9
[3,2,2,1,1] => 7
[3,2,1,1,1,1] => 5
[3,1,1,1,1,1,1] => 3
[2,2,2,2,1] => 5
[2,2,2,1,1,1] => 4
[2,2,1,1,1,1,1] => 3
[2,1,1,1,1,1,1,1] => 2
[1,1,1,1,1,1,1,1,1] => 1
[10] => 42
[9,1] => 30
[8,2] => 33
[8,1,1] => 22
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Description
The number of refinements of a partition.
A partition $\lambda$ refines a partition $\mu$ if the parts of $\mu$ can be subdivided to obtain the parts of $\lambda$.
A partition $\lambda$ refines a partition $\mu$ if the parts of $\mu$ can be subdivided to obtain the parts of $\lambda$.
References
[1] Birkhoff, G. Lattice theory MathSciNet:0598630
[2] Ziegler, Günter M. On the poset of partitions of an integer MathSciNet:0847552
[3] Perry, J. M. Counting refinements of partitions MathOverflow:226656
[2] Ziegler, Günter M. On the poset of partitions of an integer MathSciNet:0847552
[3] Perry, J. M. Counting refinements of partitions MathOverflow:226656
Code
@cached_function
def PartitionPoset(n):
return posets.IntegerPartitions(n)
def statistic(part):
P = PartitionPoset(sum(part))
return len(P.order_filter([tuple(part)]))
Created
Dec 23, 2015 at 14:54 by Christian Stump
Updated
Oct 29, 2017 at 20:56 by Martin Rubey
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