On the Erd\H{o}s-P\'osa property for immersions and topological minors in tournaments

نویسندگان

چکیده

We consider the Erd\H{o}s-P\'osa property for immersions and topological minors in tournaments. prove that every simple digraph $H$, $k\in \mathbb{N}$, tournament $T$, following statements hold: (i) If $T$ one cannot find $k$ arc-disjoint immersion copies of then there exists a set $\mathcal{O}_H(k^3)$ arcs intersects all $H$ $T$. (ii) vertex-disjoint minor $\mathcal{O}_H(k\log k)$ vertices This improves results Raymond [DMTCS '18], who proved similar under assumption is strongly connected.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Hitting minors, subdivisions, and immersions in tournaments

The Erdős–Pósa property relates parameters of covering and packing of combinatorial structures and has been mostly studied in the setting of undirected graphs. In this note, we use results of Chudnovsky, Fradkin, Kim, and Seymour to show that, for every directed graph H (resp. strongly-connected directed graph H), the class of directed graphs that contain H as a strong minor (resp. butterfly mi...

متن کامل

The Erdos-Posa Property for Directed Graphs

A classical result by Erdős and Pósa[3] states that there is a function f : N → N such that for every k, every graph G contains k pairwise vertex disjoint cycles or a set T of at most f(k) vertices such that G− T is acyclic. The generalisation of this result to directed graphs is known as Younger’s conjecture and was proved by Reed, Robertson, Seymour and Thomas in 1996. This so-called Erdős-Pó...

متن کامل

the search for the self in becketts theatre: waiting for godot and endgame

this thesis is based upon the works of samuel beckett. one of the greatest writers of contemporary literature. here, i have tried to focus on one of the main themes in becketts works: the search for the real "me" or the real self, which is not only a problem to be solved for beckett man but also for each of us. i have tried to show becketts techniques in approaching this unattainable goal, base...

15 صفحه اول

Logarithmically small minors and topological minors

For every integer t there is a smallest real number c(t) such that any graph with average degree at least c(t) must contain a Kt-minor (proved by Mader). Improving on results of Shapira and Sudakov, we prove the conjecture of Fiorini, Joret, Theis and Wood that any graph with n vertices and average degree at least c(t) + ε must contain a Kt-minor consisting of at most C(ε, t) logn vertices. Mad...

متن کامل

On Topological Minors in Random Simplicial Complexes

Simplicial Complexes. A (finite abstract) simplicial complex is a finite set system that is closed under taking subsets, i.e., F ⊂ H ∈ X implies F ∈ X. The sets F ∈ X are called faces of X. The dimension of a face F is dim(F ) = |F | − 1. The dimension of X is the maximal dimension of any face. A k-dimensional simplicial complex will also be called a k-complex.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Discrete Mathematics & Theoretical Computer Science

سال: 2022

ISSN: ['1365-8050', '1462-7264']

DOI: https://doi.org/10.46298/dmtcs.7099