48 search results - page 6 / 10 » ejc 2006 |
EJC
2006
13 years 9 months ago
2006
We introduce a large self-dual class of simplicial complexes for which we show that each member complex is contractible or homotopy equivalent to a sphere. Examples of complexes i...
EJC
2006
13 years 9 months ago
2006
In this paper we study the sequence (ci)0id for a distance-regular graph. In particular we show that if d 2j and cj = c > 1 then c2j > c holds. Using this we give improveme...
EJC
2006
13 years 9 months ago
2006
We apply Computational Algebra methods to the construction of Hadamard matrices with two circulant cores, given by Fletcher, Gysin and Seberry. We introduce the concept of Hadamar...
EJC
2006
13 years 9 months ago
2006
A class C of graphs is said to be H-bounded if each graph in the class C admits a homomorphism to H. We give a general necessary and sufficient condition for the existence of boun...
EJC
2006
13 years 9 months ago
2006
As a generalization of Deza graphs, we introduce Deza digraphs and describe the basic theory of these graphs. We also prove the necessary and sufficient conditions when a weakly d...