Identifier
- St000854: Finite Cartan types ⟶ ℤ
Values
=>
Cc0022;cc-rep
['A',1]=>1
['A',2]=>1
['B',2]=>2
['G',2]=>2
['A',3]=>1
['B',3]=>2
['C',3]=>2
['A',4]=>1
['B',4]=>2
['C',4]=>2
['D',4]=>1
['F',4]=>2
['A',5]=>1
['B',5]=>2
['C',5]=>2
['D',5]=>1
['A',6]=>1
['B',6]=>2
['C',6]=>2
['D',6]=>1
['E',6]=>1
['A',7]=>1
['B',7]=>2
['C',7]=>2
['D',7]=>1
['E',7]=>1
['A',8]=>1
['B',8]=>2
['C',8]=>2
['D',8]=>1
['E',8]=>1
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Description
The number of orbits of reflections of a finite Cartan type.
Let $W$ be the Weyl group of a Cartan type. The reflections in $W$ are closed under conjugation, and this statistic counts the number of conjugacy classes of $W$ that are reflections.
It is well-known that there are either one or two such conjugacy classes.
Let $W$ be the Weyl group of a Cartan type. The reflections in $W$ are closed under conjugation, and this statistic counts the number of conjugacy classes of $W$ that are reflections.
It is well-known that there are either one or two such conjugacy classes.
Code
def statistic(cartan_type): W = ReflectionGroup(cartan_type) return sum( 1 for w in W.conjugacy_classes_representatives() if w.is_reflection() )
Created
Jun 25, 2017 at 10:15 by Christian Stump
Updated
Jun 25, 2017 at 10:15 by Christian Stump
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