Using a recent result of Chudnovsky, Seymour, and Sullivan, we slightly improve two bounds related to the Caccetta-Haggkvist Conjecture. Namely, we show that if α ≥ 0.35312, th...
Peter Hamburger, Penny E. Haxell, Alexandr V. Kost...
New cyclic n-digit Gray codes are constructed over {0, 1, . . . , R−1} for all R ≥ 3, n ≥ 2. These codes have the property that the distribution of the digit changes (transi...
We generalize the classical work of de Bruijn, Knuth and Rice (giving the asymptotics of the average height of Dyck paths of length n) to the case of p–watermelons with a wall (...
A graph is self-complementary if it is isomorphic to its complement. In this paper we prove that every forest of order 4p and size less than 3p is a subgraph of a self-complementa...
In 2006, Smith et al. published a new table of constant weight codes, updating existing tables originally created by Brouwer et al. This paper improves upon these results by fill...
In this paper, we study the simple eigenvectors of two hypomorphic matrices using linear algebra. We also give new proofs of results of Godsil and McKay.
It is shown that the (diagonal) size Ramsey numbers of complete m-partite graphs Km(n) can be bounded from below by cn22(m−1)n, where c is a positive constant. Key words: Size R...
It is well-known that Sturmian sequences are the non ultimately periodic sequences that are balanced over a 2-letter alphabet. They are also characterized by their complexity: the...