My Papers

Sets with small product, in preparation
A generalization of Kneser's addition theorem (with L. Goddyn, and B. Mohar) submitted
A quadratic lower bound for subset sums (with L. Goddyn, B. Mohar, and R. Šamal) Acta Arithmetica 129 (2007) 187--195.
A short proof of Kneser's addition theorem, submitted

An analogue of the Descarte-Euler formula for infinite graphs and Higuchi's conjecture (with B. Mohar) Trans. Amer. Math. Soc. 359 (2007) 3287-3300.
Cayley sum graphs and eigenvalues of (3,6)-fullerines (with L. Goddyn, B. Mohar, and R. Šamal) submitted
Jorgensen's conjecture for large graphs (with R. Hegde, K. Kawarabayashi, S. Norine, R. Thomas, and P. Wollan) in preparation.
Unexpected behavior of crossing sequences (with B. Mohar, and R. Šamal) in preparation
Immersions of complete graphs (with K. Kawarabayashi, B. Mohar, H. Okamura) in preparation.
Excluding any graph as a minor allows a low tree-width 2-coloring (with G. Ding, B. Oporowski, D. P. Sanders, B. Reed, P. D. Seymour, and D. Vertigan) J. Combin. Theory Ser. B 91 (2004), no. 1, 25--41.

Cut coloring and circuit covering (with T. Johnson, and P. D. Seymour)
Flows in bidirected graphs in preparation.
On edge-maps whose inverse preserves flows or tensions (with J. Nešetřil, and A. Raspaud) Graph theory in Paris, 109--138, Trends Math., Birkhuser, Basel, 2007.
Nowhere-zero Z_3-flows through Z_3-connectivity (with R. Xu, and G. Yu) Discrete Math. 306 (2006), no. 1, 26--30.
Coloring-flow duality of graphs on surfaces (with L. Goddyn, B. Mohar, D. Vertigan, and X. Zhu) Trans. AMS 357 (2005) 3993-4016.
Antisymmetric flows and edge-connectivity (with J. Nešetřil, and A. Raspaud) Discrete Math. 276 (2004), no. 1-3, 161--167.
Matrix choosability J. Combin. Theory Ser. A 90 (2000), no. 1, 197--209.

Locally planar graphs are 5-choosable (with K. Kawarabayashi, and B. Mohar) in print JCTB
High girth cubic graphs map to the Clebsch Graph (with R. Šamal) submitted.
Planar graphs of girth > 10 map to C_5 (with A. Deckelbaum)
Extending 3-colorings of planar graphs (with P. D. Seymour) J. Combin. Theory Ser. B 88 (2003), no. 2, 219--225.
Circular coloring the plane (with J. Ebrahimi, M. Ghebleh, L. Goddyn, B. Mohar, and R. Naserasr) SIAM J. Discrete Math. 21 (2007), no. 2, 461--465.
On coloring the orthogonality graph (with L. Goddyn, B. Mohar, and R. Naserasr) in preparation.

On packing T-joins (with P. D. Seymour)
Circuits of small weight in matroids (with L. Goddyn, K. Kawarabayashi, and B. Mohar) in preparation.

Evolutionarily distinct species capture more phylogenetic diversity than expected (with Redding, Hartmann, Mimoto, Bokal, and Mooers) J. Theor. Biol. accepted.
Finding one tight cycle (with Cabello, Erickson, and Mohar) to appear in SODA 2008.
Expected case for projecting points (with Cabello and Mohar) Informatica 30 (2006) 289--293.