COMBINATORICS
2007
13 years 11 months ago
2007
COMBINATORICS
2007
13 years 11 months ago
2007
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...
COMBINATORICS
2007
13 years 11 months ago
2007
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...
COMBINATORICS
2007
13 years 11 months ago
2007
COMBINATORICS
2007
13 years 11 months ago
2007
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 (...
COMBINATORICS
2007
13 years 11 months ago
2007
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...
COMBINATORICS
2007
13 years 11 months ago
2007
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...
COMBINATORICS
2007
13 years 11 months ago
2007
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.
COMBINATORICS
2007
13 years 11 months ago
2007
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...
COMBINATORICS
2007
13 years 11 months ago
2007
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...