Hajime Tanaka

activity

20062026

most citedDistance-regular graphs

186 citations · 467 across the 31 of their papers we have counts for

collaborators

Showing 2010 · math.COShow all

3 papers · 2 filters

math.CO2010★ 16 cited

The Erdős-Ko-Rado theorem for twisted Grassmann graphs

Hajime Tanaka

We present a "modern" approach to the Erdős-Ko-Rado theorem for Q-polynomial distance-regular graphs and apply it to the twisted Grassmann graphs discovered in 2005 by van Dam and…

math.CO2010★ 2 cited

Vertex subsets with minimal width and dual width in $Q$ -polynomial distance-regular graphs

Hajime Tanaka

We study $Q$ -polynomial distance-regular graphs from the point of view of what we call descendents, that is to say, those vertex subsets with the property that the width $w$ and du…

math.CO2010★ 10 cited

Nonexistence of exceptional imprimitive Q-polynomial association schemes with six classes

Hajime Tanaka, Rie Tanaka

Suzuki (1998) showed that an imprimitive Q-polynomial association scheme with first multiplicity at least three is either Q-bipartite, Q-antipodal, or with four or six classes. The…

The Erdős-Ko-Rado theorem for twisted Grassmann graphs

Vertex subsets with minimal width and dual width in Q-polynomial distance-regular graphs

Nonexistence of exceptional imprimitive Q-polynomial association schemes with six classes

Vertex subsets with minimal width and dual width in $Q$ -polynomial distance-regular graphs