3 papers
math.CO2015
On the number of touching pairs in a set of planar curves
Péter Györgyi, Bálint Hujter, Sándor Kisfaludi-Bak
Given a set of planar curves (Jordan arcs), each pair of which meets -- either crosses or touches -- exactly once, we establish an upper bound on the number of touchings. We show t…
math.CO2015
Chip-firing based methods in the Riemann--Roch theory of directed graphs
Bálint Hujter, Lilla Tóthmérész
Baker and Norine proved a Riemann--Roch theorem for divisors on undirected graphs. The notions of graph divisor theory are in duality with the notions of the chip-firing game of Bj…
math.CO2015
On the complexity of the chip-firing reachability problem
Bálint Hujter, Viktor Kiss, Lilla Tóthmérész
In this paper, we study the complexity of the chip-firing reachability problem. We show that for Eulerian digraphs, the reachability problem can be decided in strongly polynomial t…