Results 41 to 50 of about 995,571 (241)

Excluded subposets in the Boolean lattice [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2005
We are looking for the maximum number of subsets of an n-element set not containing 4 distinct subsets satisfying $A ⊂B, C ⊂B, C ⊂D$. It is proved that this number is at least the number of the $\lfloor \frac{n }{ 2}\rfloor$ -element sets times $1+\frac ...
Gyula O.H. Katona
doaj   +1 more source

An Extremal Problem for Finite Lattices

open access: yesTheory and Applications of Graphs, 2016
For a fixed M x N integer lattice L(M,N), we consider the maximum size of a subset A of L(M,N) which contains no squares of prescribed side lengths k(1),...,k(t).
John Goldwasser   +2 more
doaj   +1 more source

Positional Games [PDF]

open access: yes, 2014
Positional games are a branch of combinatorics, researching a variety of two-player games, ranging from popular recreational games such as Tic-Tac-Toe and Hex, to purely abstract games played on graphs and hypergraphs.
Krivelevich, Michael
core   +1 more source

A characterization of extremal graphs with no matching-cut [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2005
A graph is called (matching-)immune if it has no edge cut that is also a matching. Farley and Proskurowski proved that for all immune graphs $G=(V,E)$, $|E|≥\lceil 3(|V|-1)/2\rceil$ , and constructed a large class of immune graphs that attain this lower ...
Paul Bonsma
doaj   +1 more source

Extremal properties of (epi)Sturmian sequences and distribution modulo 1 [PDF]

open access: yes, 2009
Starting from a study of Y. Bugeaud and A. Dubickas (2005) on a question in distribution of real numbers modulo 1 via combinatorics on words, we survey some combinatorial properties of (epi)Sturmian sequences and distribution modulo 1 in connection to ...
Allouche, Jean-Paul, Glen, Amy
core   +3 more sources

List graphs and distance-consistent node labelings

open access: yesElectronic Journal of Graph Theory and Applications, 2018
In this paper we consider node labelings c of an undirected connected graph G = (V, E) with labels {1, 2, ..., ∣V∣}, which induce a list distance c(u, v) = ∣c(v) − c(u)∣ besides the usual graph distance d(u, v).
Håkan Lennerstad, Mattias Eriksson
doaj   +1 more source

An extremal problem on trees and database theory [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2005
We consider an extremal problem on labelled directed trees and applications to database theory. Among others, we will show explicit keysystems on an underlying set of size $n$, that cannot be represented by a database of less than $2^{n(1-c\cdot \log ...
Gyula O.H. Katona, Krisztián Tichler
doaj   +1 more source

Recent Trends in Combinatorics [PDF]

open access: yes, 2016
Section 1: Extremal and Probabilistic Combinatorics -- Problems Related to Graph Indices in Trees -- The edit distance in graphs: methods, results and generalizations -- Repetitions in graphs and sequences -- On Some Extremal Problems for Cycles in ...
Beveridge, Andrew   +5 more
core   +3 more sources

Donaldson-Thomas invariants, torus knots, and lattice paths [PDF]

open access: yes, 2018
In this paper we find and explore the correspondence between quivers, torus knots, and combinatorics of counting paths. Our first result pertains to quiver representation theory -- we find explicit formulae for classical generating functions and ...
Panfil, Miłosz   +2 more
core   +3 more sources

Hypergraphs with infinitely many extremal constructions

open access: yesDiscrete Analysis, 2023
Hypergraphs with infinitely many extremal constructions, Discrete Analysis 2023:18, 34 pp. A fundamental result in extremal graph theory, Turán's theorem, states that the maximal number of edges of a graph with $n$ vertices that does not contain a ...
Jianfeng Hou   +4 more
doaj   +1 more source

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