DM
1999
14 years 7 days ago
1999
We say (n, e) (m, f), an (m, f) subgraph is forced, if every n-vertex graph of size e has an m-vertex spanned subgraph with f edges. For example, as Tur
DM
1999
14 years 7 days ago
1999
For an arbitrary subset P of the reals, we define a function f: V P to be a Pdominating function of graph G = (V, E) if the sum of the function values over any
DM
1999
14 years 7 days ago
1999
A defining set (of vertex coloring) of a graph G is a set of vertices S with an assignment of colors to its elements which has a unique completion to a proper coloring of G. We de...
DM
1999
14 years 7 days ago
1999
Mosaics are orbits of partitions arising from music theoretical investigations. Various theorems from the field of "enumeration under finite group actions" are applied f...
DM
1999
14 years 7 days ago
1999
Let Fk(x) = n=0 Fk n xn . Using the interpretation of Fibonacci numbers in the terms of Morse codes, we give a bijective proof of Riordan's formula (1 - Lkx + (-1)k x2 )Fk(x...
DM
1999
14 years 7 days ago
1999
We characterize bipartite Steinhaus graphs in three ways by partitioning them into four classes and we describe the color sets for each of these classes. An interesting recursion ...
DM
1999
14 years 7 days ago
1999
Let G be a simple graph with n( 2) vertices, and i(G) be the ith largest eigenvalue of G. In this paper we obtain the following: If 3(G) < 0, and there exists some index k, 2 ...
DM
1999
14 years 7 days ago
1999
DM
1999
14 years 7 days ago
1999
We construct a bijection between labeled trees and allowable pairs of permutations sorted by a priority queue. These are also the pairs of permutations that avoid the pattern pairs...
DM
1999
14 years 7 days ago
1999