1 citations · 2 across the 7 of their papers we have counts for
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From Bruhat intervals to intersection lattices and a conjecture of Postnikov
Axel Hultman, Svante Linusson, John Shareshian +1
We prove the conjecture of A. Postnikov that (A) the number of regions in the inversion hyperplane arrangement associated with a permutation $w\in \Sn$ is at most the number of ele…
Bruhat intervals as rooks on skew Ferrers boards
Jonas Sjostrand
We characterise the permutations pi such that the elements in the closed lower Bruhat interval [id,pi] of the symmetric group correspond to non-taking rook configurations on a skew…
Note on the lamp lighting problem
Henrik Eriksson, Kimmo Eriksson, Jonas Sjostrand
We answer some questions concerning the so called sigma-game of Sutner. It is played on a graph where each vertex has a lamp, the light of which is toggled by pressing any vertex w…
Exact expectations for random graphs and assignments
Henrik Eriksson, Kimmo Eriksson, Jonas Sjostrand
For a random graph on n vertices where the edges appear with individual rates, we give exact formulas for the expected time at which the number of components has gone down to k and…
Bier spheres and posets
Anders Björner, Andreas Paffenholz, Jonas Sjöstrand +1
In 1992 Thomas Bier presented a strikingly simple method to produce a huge number of simplicial (n-2)-spheres on 2n vertices as deleted joins of a simplicial complex on n vertices…
On the sign-imbalance of partition shapes
Jonas Sjöstrand
Let the sign of a standard Young tableau be the sign of the permutation you get by reading it row by row from left to right, like a book. A conjecture by Richard Stanley says that…