All Questions
6 questions
12
votes
1
answer
385
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Question on a reduction in Kirillov's paper on positivity of divided difference operators
As the title says, my question is on a specific argument in Kirillov - Skew divided difference operators and Schubert polynomials (journal, MSN) on positivity of divided difference operators. I recall ...
7
votes
1
answer
591
views
Can Matsumoto's theorem for the symmetric group be proved using a monovariant?
This is a question that can be asked for any Coxeter group, but for the sake of simplicity I will restrict myself to symmetric groups. Recall the main definitions:
Let $n$ be a nonnegative integer. ...
4
votes
0
answers
145
views
Words that give rise to an enumeration of elements of the symmetric group
Let $\mathbb{S}_m$ be the symmetric group on $m$ letters. Let $n=m-1$. Let $\mathbf{w}=a_1\cdots a_r$ be a word on the alphabet $\{1,\ldots,n\}$. We say that $\mathbf{w}$ gives rise to an enumeration ...
1
vote
0
answers
147
views
A certain kind of permutations and transport of Bruhat chains under conjugation
Let $(W,S)$ be a finite Coxeter system. Let us consider the following situation:
Let $v_1,v_2,w\in W$ such that $v_1=wv_2w^{-1}$. Let $s_{\beta_r}\ldots s_{\beta_1}$ be a reduced expression of $v_2$. ...
2
votes
0
answers
81
views
Characterization of permutations which have at most one successor in the covering relation of the weak Bruhat order
Let $W$ be the symmetric group on $n+1$ letters. Let $\ell$ be the length function on $W$.
As the title says, can we characterize all $v\in W$ such that there exists a $w\in W$ such that for all ...
4
votes
3
answers
947
views
Maximal pairwise distance between $k$ permutations
How can k permutations on n-set be arranged to maximize minimal pairwise Kendall tau distance (i.e. number of discordant pairs) between them?
For two permutations this is obviously when the second ...