178 search results - page 13 / 36 » combinatorics 2007 |
73
Voted
COMBINATORICS
2007
15 years 19 days ago
2007
We refine previous results to provide examples, and in some cases precise classifications, of extremal subsets of {1, ..., n} containing no solutions to a wide class of non-inva...
84
Voted
COMBINATORICS
2007
15 years 19 days ago
2007
Suppose xm + axn is a permutation polynomial over Fp, where p > 5 is prime and m > n > 0 and a ∈ F∗ p. We prove that gcd(m−n, p−1) /∈ {2, 4}. In the special cas...
68
Voted
COMBINATORICS
2007
15 years 19 days ago
2007
We present an infinite family of 3-connected non-bipartite graphs with chromatic roots in the interval (1, 2) thus resolving a conjecture of Jackson’s in the negative. In addit...
103
Voted
COMBINATORICS
2007
15 years 19 days ago
2007
We define a partial order on colored compositions with many properties analogous to Young’s lattice. We show that saturated chains correspond to colored permutations, and that ...
102
Voted
COMBINATORICS
2007
15 years 19 days 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...