COMBINATORICS
2007
13 years 11 months ago
2007
COMBINATORICS
2007
13 years 11 months ago
2007
A permutation class which is closed under pattern involvement may be described in terms of its basis. The wreath product construction X Y of two permutation classes X and Y is als...
COMBINATORICS
2007
13 years 11 months ago
2007
The density matrix of a graph is the combinatorial laplacian matrix of a graph normalized to have unit trace. In this paper we generalize the entanglement properties of mixed dens...
COMBINATORICS
2007
13 years 11 months ago
2007
In 1995, Hochberg, McDiarmid, and Saks proved that the vertex-bandwidth of the triangular grid Tn is precisely n + 1; more recently Balogh, Mubayi, and Pluh´ar posed the problem ...
COMBINATORICS
2007
13 years 11 months ago
2007
We study the shape of the Young diagram λ associated via the Robinson– Schensted–Knuth algorithm to a random permutation in Sn such that the length of the longest decreasing ...
COMBINATORICS
2007
13 years 11 months ago
2007
A k-ary necklace of order n is an equivalence class of strings of length n of symbols from {0, 1, . . . , k − 1} under cyclic rotation. In this paper we define an ordering on t...
COMBINATORICS
2007
13 years 11 months ago
2007
We use methods of combinatorics of polytopes together with geometrical and computational ones to obtain the complete list of compact hyperbolic Coxeter npolytopes with n + 3 facet...
COMBINATORICS
2007
13 years 11 months 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...
COMBINATORICS
2007
13 years 11 months ago
2007
COMBINATORICS
2007
13 years 11 months ago
2007
The distinguishing number ∆(X) of a graph X is the least positive integer n for which there exists a function f : V (X) → {0, 1, 2, · · · , n−1} such that no nonidentity ...