Recent (and not-so-recent) papers

Preprint versions, pdf files


Filtered geometric lattices and Lefschetz section theorems over the tropical semiring
(with K. Adiprasato), preprint 2014 (28 pp).
(Also at
http://arxiv.org/abs/1401.7301 )


A cell complex in number theory
Preprint 2009 (16 pp)
Advances in Appl. Math. 46 (2011), 71--85.   

(Also at http://arXiv.org/abs/1101.5704 )


On sequentially Cohen-Macaulay complexes and posets (with M. Wachs and V. Welker)

Preprint 2007 (19 pp) 

Israel Journal of Mathematicss 169 (2009), 295--316. 

(Also at http://arXiv.org/math/0702788 )


Connectivity of chamber graphs of buildings and related complexes (with K. Vorwerk)
Preprint 2009 (14 pp)
Europ. J. Combinatorics 31 (2010), 2149--2160.
(Also at
http://arXiv.org/abs/0907.0325 )


A q-analogue of the FKG inequality and some applications

Preprint 2009 (11 pp)
Combinatorica 31 (2011), 151--164.
(Also at
http://arXiv.org/abs/0906.1389 )


Note: Random-to-front shuffles on trees

Preprint 2008 (6 pp)
Electronic Comm. in Probability 14 (2009), 36--41.
(Also at
http://arXiv.org/abs/0901.4278 )


Random walks, arrangements, cell complexes, greedoids, and self-organizing libraries

Preprint 2008 (30 pp)
In "Building bridges --- the Lov'asz Festschrift" (eds. M. Groetschel and G. O. H. Katona),
Bolyai Soc. Math. Studies 19 (2008), Springer, Berlin and Budapest, pp. 165--203.
(Also at
http://arXiv.org/abs/0805.0083 )


Appendix to "Hyperplane arrangements and box splines" by C. De Concini and C. Procesi

Preprint 2007 (4 pp)
Michigan Math. Journal 57 (2008), 221--225. 


On sequentially Cohen-Macaulay complexes and posets
(with M. Wachs and V. Welker)
Preprint 2007 (19 pp)
Israel Journal of Mathematicss 169 (2009), 295--316.
(Also at
http://arXiv.org/math/0702788 )


Combinatorial Alexander duality --- a short and elementary proof
(with M. Tancer)
Preprint 2007 (7 pp)
Discrete and Computational Geometry 42 (2009), 586--593.
(Also at
http://arXiv.org/abs/0710.1172


A comparison theorem for $f$-vectors of simplicial polytopes
Preprint 2006 (8 pp)
Pure and Applied Mathematics Quarterly 3 (2007), 347--356.
(Also at
http://arXiv.org/math/0605336 )


Rationality of the M\"obius function of a composition poset (with B. E. Sagan)
Preprint 2005 (20 pp)
Theoretical Computer Science 359 (2006), 282--298.
(Also at
http://arXiv.org/math/0510282 )


An analogue of Young’s lattice for compositions (with R. P. Stanley)
Preprint 2005 (20 pp)


On the shape of Bruhat intervals (with T. Ekedahl)
Preprint 2005 (15 pp)
Annals of Mathematics 170:2 (2009), 799--817.
(Also at
http://arXiv.org/math/0508022 )


Topological Combinatorics
Slides from lecture given at the R. MacPherson 60th birthday symposium,
IAS, Princeton, October 2004.


Chain polynomials of distributive lattices are 75 % unimodal
(with J. D. Farley)
Preprint 2004 (7 pp)
Electronic Journal of Combinatorics 12 (2005), N4.
(Also at
http://arXiv.org/math/0411610 )


A note on blockers in posets (with A. Hultman)
Preprint 2004 (11 pp)
Annals of Combinatorics 8 (2004), 123--131.
(Also at
http://arXiv.org/math/0403094 )


Subspace arrangements defined by products of linear forms (with I. Peeva and J. Sidman)
Preprint 2003 (20 pp)
Journal of the London Math. Society 71 (2005), 273--288.
(Also at
http://arXiv.org/math/0401373 )


Bier spheres and posets (with A. Paffenholz, J. Sj\"ostrand and G. M. Ziegler)
Preprint 2003 (15 pp)
Discrete and Computational Geometry 34 (2005), 471--86.
(Also at
http://arXiv.org/math/0311356 )


Segre and Rees products of posets, with ring-theoretic applications (with V. Welker)
Preprint 2003 (12 pp) Journal of Pure and Applied Algebra 198 (2005), 43--55.
(Also at
http://arXiv.org/math/0312516 )


Poset fiber theorems (with M. Wachs and V. Welker)
Preprint 2002 (30 pp)
Trans. Amer. Math. Soc., 357 (2004), 1877--1899. 


Nerves, fibers and homotopy groups,
Preprint 2002 (6 pp)
J. Combinatorial Theory, Ser. A, 102 (2003), 88--93.


Neighborhood complexes of stable Kneser graphs (with M. de Longueville)
Preprint 2001 (12 pp)
Combinatorica 23 (2003), 23--34.


Geometrically constructed bases for homology of partition lattices of types $A$, $B$ and $D$ (with M. Wachs)
Preprint 2001 (29 pp) (Also at
http://arXiv.org/abs/math/0401006 )
Electronic Journal of Combinatorics 11 (2) (2004), #R3.


Simplicial manifolds, bistellar flips and a 16-vertex triangulation of the Poincare homology 3-sphere (with F. H. Lutz)
Preprint 1999 (22 pp)
Experimental Mathematics 21 (2000), 275--289.


Face numbers of Scarf complexes
Preprint 1998 (12 pp)
Discrete and Computational Geometry 24 (2000), 185--196.


A combinatorial miscellany (with R. P. Stanley)
Preprint 1998 (93 pp)


Complexes of directed graphs (with V. Welker)
Preprint 1998 (13 pp)
SIAM Journal on Discrete Mathematics 12 (1999), 413--424.


Complexes of not $i$-connected graphs (with E. Babson, S. Linusson, J. Shareshian and V. Welker)
Preprint 1997 (28 pp)
Topology 38 (1999), 271--299.


The number of k-faces of a simple d-polytope (with S. Linusson)
Preprint 1997 (16 pp)

Discrete and computational geometry
21 (1999), 1--16.

Subspace arrangements over finite fields (with T. Ekedahl)
Preprint 1996 (26 pp)
Advances in Mathematics 129 (1997), 159--187.


Topological Methods
in ``Handbook of Combinatorics'' (eds. R. Graham, M. Gr\"otschel and L. Lov\'asz),
North-Holland, Amsterdam, 1995, pp. 1819--1872.


(>\s‚”ž¤¥ò 3$