47 citations · 678 across the 85 of their papers we have counts for
5 papers · 1 filter
Hyperbolic surface subgroups of one-ended doubles of free groups
Sang-hyun Kim, Sang-il Oum
Gromov asked whether every one-ended word-hyperbolic group contains a hyperbolic surface group. We prove that every one-ended double of a free group has a hyperbolic surface subgro…
Rank-width and Well-quasi-ordering of Skew-Symmetric or Symmetric Matrices
Sang-il Oum
We prove that every infinite sequence of skew-symmetric or symmetric matrices M_1, M_2, ... over a fixed finite field must have a pair M_i, M_j (i<j) such that M_i is isomorphic to…
Classification of real Bott manifolds and acyclic digraphs
Suyoung Choi, Mikiya Masuda, Sang-il Oum
We completely characterize real Bott manifolds up to affine diffeomorphism in terms of three simple matrix operations on square binary matrices obtained from strictly upper triangu…
Real Bott manifolds and acyclic digraphs
Suyoung Choi, Sang-il Oum
Masuda (2008) provided the characterization of real Bott manifolds in terms of three operations on upper triangular matrices. We provide a combinatorial characterization of real Bo…
Rank-width of Random Graphs
Choongbum Lee, Joonkyung Lee, Sang-il Oum
Rank-width of a graph G, denoted by rw(G), is a width parameter of graphs introduced by Oum and Seymour (2006). We investigate the asymptotic behavior of rank-width of a random gra…