12 citations · 12 across the 2 of their papers we have counts for
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math.CO2019
Seymour's second-neighborhood conjecture from a different perspective
Farid Bouya, Bogdan Oporowski
Seymour's Second-Neighborhood Conjecture states that every directed graph whose underlying graph is simple has at least one vertex such that the number of vertices of out-dista…
math.CO2006
Unavoidable Parallel Minors of 4-Connected Graphs
Carolyn Chun, Guoli Ding, Bogdan Oporowski +1
A parallel minor is obtained from a graph by any sequence of edge contractions and parallel edge deletions. We prove that, for any positive integer k, every internally 4-connected…
math.CO2005★ 12 cited
Coloring graphs with crossings
Bogdan Oporowski, David Zhao
We generalize the Five Color Theorem by showing that it extends to graphs with two crossings. Furthermore, we show that if a graph has three crossings, but does not contain K_6 as…