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Positive expressions for skew divided difference operators
For permutations v , w ∈ S n , Macdonald defines the skew divided difference operators ∂ w / v as the unique linear operators satisfying ∂ w ( P Q ) = ∑ v v ( ∂ w / v P ) · ∂ v Q for all polynomials P and Q . We prove that ∂ w / v has a positive expression in terms of divided difference operators ∂...
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Published in: | Journal of algebraic combinatorics 2015-11, Vol.42 (3), p.861-874 |
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Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | For permutations
v
,
w
∈
S
n
, Macdonald defines the skew divided difference operators
∂
w
/
v
as the unique linear operators satisfying
∂
w
(
P
Q
)
=
∑
v
v
(
∂
w
/
v
P
)
·
∂
v
Q
for all polynomials
P
and
Q
. We prove that
∂
w
/
v
has a positive expression in terms of divided difference operators
∂
i
j
for
i
<
j
. In fact, we prove that the analogous result holds in the Fomin–Kirillov algebra
E
n
, which settles a conjecture of Kirillov. |
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ISSN: | 0925-9899 1572-9192 |
DOI: | 10.1007/s10801-015-0606-1 |