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DM
2006
135views more  DM 2006»
13 years 11 months ago
Berge's conjecture on directed path partitions - a survey
Berge's conjecture from 1982 on path partitions in directed graphs generalizes and extends Dilworth's Theorem and the Greene-Kleitman Theorem which are well known for pa...
Irith Ben-Arroyo Hartman
DM
2006
92views more  DM 2006»
13 years 11 months ago
Sums of powers of the degrees of a graph
For a graph G and k a real number, we consider the sum of the k-th powers of the degrees of the vertices of G. We present some general bounds on this sum for various values of k. ...
Sebastian M. Cioaba
DM
2006
70views more  DM 2006»
13 years 11 months ago
Transversals in long rectangular arrays
In this paper it is shown that every m
Saeed Akbari, O. Etesami, H. Mahini, M. Mahmoody, ...
DM
2006
63views more  DM 2006»
13 years 11 months ago
Efficient crossover designs for comparing test treatments with a control treatment
Within a large family of crossover designs this paper characterizes the mathematical structures of A-optimal and A-efficient crossover designs for the purpose of statistical compa...
A. Sadam Hedayat, Min Yang
DM
2006
68views more  DM 2006»
13 years 11 months ago
A note on maximally repeated sub-patterns of a point set
We answer a question raised by Brass on the number of maximally repeated sub-patterns in a set of n points in Rd. We show that this number, which was conjectured to be polynomial,...
Véronique Cortier, Xavier Goaoc, Mira Lee, ...
DM
2006
73views more  DM 2006»
13 years 11 months ago
Composition of Post classes and normal forms of Boolean functions
The class composition C K of Boolean clones, being the set of composite functions f(g1, . . . , gn) with f C, g1, . . . , gn K, is investigated. This composition C K is either...
Miguel Couceiro, Stephan Foldes, Erkko Lehtonen
DM
2006
84views more  DM 2006»
13 years 11 months ago
Hamilton cycles in digraphs of unitary matrices
We conjecture new sufficient conditions for a digraph to have a Hamilton cycle. In view of applications, the conjecture is of interest in the areas where unitary matrices are of i...
Gregory Gutin, Arash Rafiey, Simone Severini, Ande...
DM
2006
72views more  DM 2006»
13 years 11 months ago
Designs on the web
R. A. Bailey, Peter J. Cameron, Peter Dobcsá...
DM
2006
72views more  DM 2006»
13 years 11 months ago
Patterson-Wiedemann construction revisited
In 1983, Patterson and Wiedemann constructed Boolean functions on n = 15 input variables having nonlinearity strictly greater than 2n-1 -2 n-1 2 . Construction of Boolean function...
Sugata Gangopadhyay, Pradipkumar H. Keskar, Subham...