Zobrazeno 1 - 10
of 28
pro vyhledávání: '"Ivan, Maria‐Romina"'
How small can a set of vertices in the $n$-dimensional hypercube $Q_n$ be if it meets every copy of $Q_d$? The asymptotic density of such a set (for $d$ fixed and $n$ large) is denoted by $\gamma_d$. It is easy to see that $\gamma_d \leq 1/(d+1)$, an
Externí odkaz:
http://arxiv.org/abs/2411.09445
A set $X$ is called Euclidean Ramsey if, for any $k$ and sufficiently large $n$, every $k$-colouring of $\mathbb{R}^n$ contains a monochromatic congruent copy of $X$. This notion was introduced by Erd\H{o}s, Graham, Montgomery, Rothschild, Spencer an
Externí odkaz:
http://arxiv.org/abs/2406.01459
An $r$-daisy is an $r$-uniform hypergraph consisting of the six $r$-sets formed by taking the union of an $(r-2)$-set with each of the 2-sets of a disjoint 4-set. Bollob\'as, Leader and Malvenuto, and also Bukh, conjectured that the Tur\'an density o
Externí odkaz:
http://arxiv.org/abs/2401.16289
Autor:
Baber, Rahil, Behague, Natalie, Calbet, Asier, Ellis, David, Erde, Joshua, Gray, Ron, Ivan, Maria-Romina, Janzer, Barnabás, Johnson, Robert, Milićević, Luka, Talbot, John, Tan, Ta Sheng, Wickes, Belinda
One of the great pleasures of working with Imre Leader is to experience his infectious delight on encountering a compelling combinatorial problem. This collection of open problems in combinatorics has been put together by a subset of his former PhD s
Externí odkaz:
http://arxiv.org/abs/2310.18163
Given a finite poset $\mathcal P$, we say that a family $\mathcal F$ of subsets of $[n]$ is $\mathcal P$-saturated if $\mathcal F$ does not contain an induced copy of $\mathcal P$, but adding any other set to $\mathcal F$ creates an induced copy of $
Externí odkaz:
http://arxiv.org/abs/2310.04634
Publikováno v:
New York Journal of Mathematics, Volume 29 (2023), 301 -- 322
Our aim in this paper is to show that, for any $k$, there is a finite colouring of the set of rationals whose denominators contain only the first $k$ primes such that no infinite set has all of its finite sums and products monochromatic. We actually
Externí odkaz:
http://arxiv.org/abs/2210.07831
Autor:
Đanković, Irina, Ivan, Maria-Romina
For a given positive integer $k$ we say that a family of subsets of $[n]$ is $k$-antichain saturated if it does not contain $k$ pairwise incomparable sets, but whenever we add to it a new set, we do find $k$ such sets. The size of the smallest such f
Externí odkaz:
http://arxiv.org/abs/2205.07392
A (finite or infinite) graph is called constructible if it may be obtained recursively from the one-point graph by repeatedly adding dominated vertices. In the finite case, the constructible graphs are precisely the cop-win graphs, but for infinite g
Externí odkaz:
http://arxiv.org/abs/2203.05487
Our aim in this note is to show that, for any $\epsilon>0$, there exists a union-closed family $\mathcal F$ with (unique) smallest set $S$ such that no element of $S$ belongs to more than a fraction $\epsilon$ of the sets in $\mathcal F$. More precis
Externí odkaz:
http://arxiv.org/abs/2201.11484
Autor:
Ivan, Maria-Romina
For a given fixed poset $\mathcal P$ we say that a family of subsets of $[n]$ is $\mathcal P$-saturated if it does not contain an induced copy of $\mathcal P$, but whenever we add to it a new set, an induced copy of $\mathcal P$ is formed. The size o
Externí odkaz:
http://arxiv.org/abs/2110.01118