Results 71 to 80 of about 14,970 (213)

SPERNER THEOREMS FOR UNRELATED COPIES OF POSETS AND GENERATING DISTRIBUTIVE LATTICES

Ural Mathematical Journal
For a finite poset (partially ordered set) \(U\) and a natural number \(n\), let \(S(U,n)\) denote the largest number of pairwise unrelated copies of  \(U\) in the powerset lattice (AKA subset lattice) of an \(n\)-element set.
Gábor Czédli
doaj   +1 more source

Hypergraph removal lemmas via robust sharp threshold theorems

Discrete Analysis, 2020
Hypergraph removal lemmas via robust sharp threshold theorems, Discrete Analysis 2020:10, 46 pp. A central result in additive and extremal combinatorics is the triangle removal lemma, which roughly speaking states that a graph with few triangles can be ...
Noam Lifshitz
doaj   +1 more source

Host Competitive Asymmetries Accelerate Viral Evolution in a Microbe–Virus Coevolutionary System

Ecology Letters, Volume 28, Issue 6, June 2025.
We examine the dynamical consequences of two concurrent and counteracting modes of selection in CRISPR‐mediated coevolution of microbial hosts and their viruses: negative frequency‐dependent selection from specific immunity in the host which promotes diversity, and directional selection from host competitive asymmetries which opposes it.
Armun Liaghat, Martin Guillemet, Rachel Whitaker, Sylvain Gandon, Mercedes Pascual   +4 more
wiley   +1 more source

Structure of hyperbolic polynomial automorphisms of C2${\mathbb {C}^2}$ with disconnected Julia sets

Proceedings of the London Mathematical Society, Volume 130, Issue 6, June 2025.
Abstract For a hyperbolic polynomial automorphism of C2$\mathbb {C}^2$ with a disconnected Julia set, and under a mild dissipativity condition, we give a topological description of the components of the Julia set. Namely, there are finitely many “quasi‐solenoids” that govern the asymptotic behavior of the orbits of all nontrivial components.
Romain Dujardin, Mikhail Lyubich
wiley   +1 more source

Beyond sum-free sets in the natural numbers [PDF]

, 2014
For an interval [1,N]⊆N, sets S⊆[1,N] with the property that |{(x,y)∈S2:x+y∈S}|=0, known as sum-free sets, have attracted considerable attention. In this paper, we generalize this notion by considering r(S)=|{(x,y)∈S2:x+y∈S}|, and analyze its behaviour ...
Huczynska, Sophie
core  

Improving bounds on packing densities of 4-point permutations

, 2018
We consolidate what is currently known about packing densities of 4-point permutations and in the process improve the lower bounds for the packing densities of 1324 and 1342.
Sliacan, Jakub, Stromquist, Walter
core   +1 more source

On Rainbow Turán Densities of Trees

Random Structures &Algorithms, Volume 66, Issue 3, May 2025.
ABSTRACT For a given collection 𝒢=(G1,…,Gk) of graphs on a common vertex set V$$ V $$, which we call a graph system, a graph H$$ H $$ on a vertex set V(H)⊆V$$ V(H)\subseteq V $$ is called a rainbow subgraph of 𝒢 if there exists an injective function ψ:E(H)→[k]$$ \psi :E(H)\to \left[k\right] $$ such that e∈Gψ(e)$$ e\in {G}_{\psi (e)} $$ for each e∈E(H)$$
Seonghyuk Im, Jaehoon Kim, Hyunwoo Lee, Haesong Seo   +3 more
wiley   +1 more source

Kneser graphs are like Swiss cheese

Discrete Analysis, 2018
Kneser graphs are like Swiss cheese, Discrete Analysis 2018:2, 18 pp. This paper relates two very interesting areas of research in extremal combinatorics: removal lemmas, and influence of variables.
Ehud Friedgut, Oded Regev
doaj   +1 more source

Restart Perturbations for Reversible Markov Chains: Trichotomy and Pre‐Cutoff Equivalence

Random Structures &Algorithms, Volume 66, Issue 3, May 2025.
ABSTRACT Given a reversible Markov chain Pn$$ {P}_n $$ on n$$ n $$ states, and another chain P˜n$$ {\tilde{P}}_n $$ obtained by perturbing each row of Pn$$ {P}_n $$ by at most αn$$ {\alpha}_n $$ in total variation, we study the total variation distance between the two stationary distributions, ‖πn−π˜n‖$$ \left\Vert {\pi}_n-{\tilde{\pi}}_n\right\Vert $$.
Daniel Vial, Vijay Subramanian
wiley   +1 more source