Arlene A. Pascasio

Learn More
In this paper, we prove the following two theorems. Theorem 1 Let 0 denote a distance-regular graph with diameter d ≥ 3. Suppose E and F are primitive idempotents of 0, with cosine sequences σ0, σ1, . . . , σd and ρ0, ρ1, . . . , ρd , respectively. Then the following are equivalent. (i) The entry-wise product E ◦ F is a scalar multiple of a primitive(More)
In this paper, we prove the following: Theorem. Let A= 〈A0; A1; : : : ; Ad〉 denote a complex character algebra with d¿ 2 which is P-polynomial with respect to the ordering A0; A1; : : : ; Ad of the distinguished basis. Assume that the structure constants p ij are all nonnegative and the Krein parameters q h ij are all nonnegative. Let and ′ denote(More)