3 papers
math.CO2022
Two flags in a semimodular lattice generate an antimatroid
Koyo Hayashi, Hiroshi Hirai
A basic property in a modular lattice is that any two flags generate a distributive sublattice. It is shown (Abels 1991, Herscovic 1998) that two flags in a semimodular lattice no…
cs.DS2022
Finding Hall blockers by matrix scaling
Koyo Hayashi, Hiroshi Hirai, Keiya Sakabe
For a given nonnegative matrix , the matrix scaling problem asks whether can be scaled to a doubly stochastic matrix for some positive diagonal matrices $…
cs.CG2017
A polynomial time algorithm to compute geodesics in CAT(0) cubical complexes
Koyo Hayashi
This paper presents the first polynomial time algorithm to compute geodesics in a CAT(0) cubical complex in general dimension. The algorithm is a simple iterative method to update…