Results 61 to 70 of about 125 (122)

On the extremal combinatorics of the hamming space

open access: yesJournal of Combinatorial Theory, Series A, 1995
In \(n\)-dimensional Hamming space three points are on a line, if they satisfy the triangle inequality with equality. The paper introduces the following problem: How many different points can be found in the Hamming space so that no three of them are on a line (that is they are in general position)? This maximum value is \(A(n)\). The paper surveys the
openaire   +3 more sources

The dimension of well approximable numbers

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 1, January 2026.
Abstract In this survey article, we explore a central theme in Diophantine approximation inspired by a celebrated result of Besicovitch on the Hausdorff dimension of well approximable real numbers. We outline some of the key developments stemming from Besicovitch's result, with a focus on the mass transference principle, ubiquity and Diophantine ...
Victor Beresnevich, Sanju Velani
wiley   +1 more source

Quasirandom Cayley graphs

open access: yesDiscrete Analysis, 2017
Quasirandom Cayley graphs, Discrete Analysis 2017:6, 14 pp. An extremely important phenomenon in extremal combinatorics is that of _quasirandomness_: for many combinatorial structures, it is possible to identify a list of deterministic properties, each ...
David Conlon, Yufei Zhao
doaj   +1 more source

On certain extremal Banach–Mazur distances and Ader's characterization of distance ellipsoids

open access: yesMathematika, Volume 72, Issue 1, January 2026.
Abstract A classical consequence of the John Ellipsoid Theorem is the upper bound n$\sqrt {n}$ on the Banach–Mazur distance between the Euclidean ball and any symmetric convex body in Rn$\mathbb {R}^n$. Equality is attained for the parallelotope and the cross‐polytope. While it is known that they are unique with this property for n=2$n=2$ but not for n⩾
Florian Grundbacher, Tomasz Kobos
wiley   +1 more source

Extremal combinatorics, iterated pigeonhole arguments, and generalizations of PPP

open access: yes, 2022
We study the complexity of computational problems arising from existence theorems in extremal combinatorics. For some of these problems, a solution is guaranteed to exist based on an iterated application of the Pigeonhole Principle. This results in the definition of a new complexity class within TFNP, which we call PLC (for "polynomial long choice ...
Pasarkar, Amol   +2 more
openaire   +4 more sources

Power saving for the Brown-Erdős-Sós problem

open access: yesDiscrete Analysis
Power saving for the Brown-Erdős-Sós problem, Discrete Analysis 2025:5, 16 pp. It has long been known that there are important connections between extremal questions concerning hypergraphs and extremal questions in additive combinatorics.
Oliver Janzer   +3 more
doaj   +1 more source

Extremal Combinatorics and Universal Algorithms

open access: yes, 2018
In this dissertation we solve several combinatorial problems in different areas of mathematics: automata theory, combinatorics of partially ordered sets and extremal combinatorics. Firstly, we focus on some new automata that do not seem to have occurred much in the literature, that of solvability of mazes.
openaire   +1 more source

Coloring and extremal problems in combinatorics

open access: yes, 2018
Coloring problems concern partitions of structures. The classic problem of partitioning the set of integers into a finite number of pieces so that no one piece has an arithmetic progression of a fixed length was solved in 1927. Van der Waerden's Theorem shows that it is impossible to do so.
openaire   +3 more sources

On problems in Extremal Combinatorics

open access: yes, 2016
Extremal Combinatorics studies how large or how small a structure can be, if it does not contain certain forbidden configuration. One of its major areas of study is extremal set theory, where the structures considered are families of sets, and the forbidden configurations are restricted intersection patterns.
openaire   +1 more source

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