演講者:潘業忠博士
單 位:國立交通大學應用數學系
日 期:2008年10月15日 PM 14:30
地 點:國立高雄大學理學院408室
講 題:Triangle-free Distance-regular Graphs with Pentagons
摘 要:
Let Γ be a distance-regular graph with classical parameters (D,b,α , β ) . Assume the diameter D ≥ 3 and the intersection numbers 0 1 a = and 0 2 a ≠ . We show the following results.
●α < 0 and b < −1.
● Γ is 3-bounded.
● The intersection number 2 c is either 1 or 2.
● If 1 2 c = then (b,α, β ) = (−2, − 2, ((−2)D+1 −1) / 3) .