12 citations · 15 across the 6 of their papers we have counts for
7 papers
Unavoidable Induced Subgraph of Infinite 2-connected Graphs
Sarah Allred, Guoli Ding, Bogdan Oporowski
In 1930, Ramsey proved that every infinite graph contains either an infinite clique or an infinite independent set as an induced subgraph. König proved that every infinite graph co…
Unavoidable Induced Subgraphs of Large 2-Connected Graphs
Sarah Allred, Guoli Ding, Bogdan Oporowski
Ramsey proved that for every positive integer , every sufficiently large graph contains an induced or . Among the many extensions of Ramsey's Theorem there…
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…
Characterizing 2-crossing-critical graphs
Drago Bokal, Bogdan Oporowski, R. Bruce Richter +1
It is very well-known that there are precisely two minimal non-planar graphs: and (degree 2 vertices being irrelevant in this context). In the language of crossing…
Large Non-Planar Graphs and an Application to Crossing-Critical Graphs
Guoli Ding, Bogdan Oporowski, Robin Thomas +1
We prove that, for every positive integer k, there is an integer N such that every 4-connected non-planar graph with at least N vertices has a minor isomorphic to K_{4,k}, the grap…
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…