17 citations · 116 across the 43 of their papers we have counts for
6 papers · 1 filter
Characterization of forbidden subgraphs for bounded star chromatic number
Ilkyoo Choi, Ringi Kim, Boram Park
The chromatic number of a graph is the minimum such that the graph has a proper -coloring. There are many coloring parameters in the literature that are proper colorings tha…
Inducibility of directed paths
Ilkyoo Choi, Bernard Lidický, Florian Pfender
A long standing open problem in extremal graph theory is to describe all graphs that maximize the number of induced copies of a path on four vertices. The character of the problem…
On operations preserving semi-transitive orientability of graphs
Ilkyoo Choi, Jinha Kim, Minki Kim
We consider the class of semi-transitively orientable graphs, which is a much larger class of graphs compared to transitively orientable graphs, in other words, comparability graph…
A Ramsey-type theorem for the matching number regarding connected graphs
Ilkyoo Choi, Michitaka Furuya, Ringi Kim +1
A major line of research is discovering Ramsey-type theorems, which are results of the following form: given a graph parameter , every graph with sufficiently large c…
Characterization of cycle obstruction sets for improper coloring planar graphs
Ilkyoo Choi, Chun-Hung Liu, Sang-il Oum
For nonnegative integers , a graph is -colorable if its vertex set can be partitioned into parts so that the th part induces a graph…
Degeneracy and Colorings of Squares of Planar Graphs without 4-Cycles
Ilkyoo Choi, Daniel W. Cranston, Théo Pierron
We prove several results on coloring squares of planar graphs without 4-cycles. First, we show that if is such a graph, then is -degenerate. This implies an up…