Tight Bounds for Embedding Bounded Degree Trees

Author(s):  
Béla Csaba ◽  
Judit Nagy-György ◽  
Ian Levitt ◽  
Endre Szemerédi
2017 ◽  
Vol 340 (12) ◽  
pp. 2798-2806
Author(s):  
L. Alcón ◽  
M. Gutierrez ◽  
M.P. Mazzoleni

2018 ◽  
Vol 27 (3) ◽  
pp. 289-309 ◽  
Author(s):  
IGOR BALLA ◽  
ALEXEY POKROVSKIY ◽  
BENNY SUDAKOV

Given a pair of graphsGandH, the Ramsey numberR(G,H) is the smallestNsuch that every red–blue colouring of the edges of the complete graphKNcontains a red copy ofGor a blue copy ofH. If a graphGis connected, it is well known and easy to show thatR(G,H) ≥ (|G|−1)(χ(H)−1)+σ(H), where χ(H) is the chromatic number ofHand σ(H) is the size of the smallest colour class in a χ(H)-colouring ofH. A graphGis calledH-goodifR(G,H) = (|G|−1)(χ(H)−1)+σ(H). The notion of Ramsey goodness was introduced by Burr and Erdős in 1983 and has been extensively studied since then.In this paper we show that ifn≥ Ω(|H| log4|H|) then everyn-vertex bounded degree treeTisH-good. The dependency betweennand |H| is tight up to log factors. This substantially improves a result of Erdős, Faudree, Rousseau, and Schelp from 1985, who proved thatn-vertex bounded degree trees areH-good whenn≥ Ω(|H|4).


1989 ◽  
Vol 2 (2) ◽  
pp. 145-155 ◽  
Author(s):  
Sandeep N. Bhatt ◽  
F. R. K. Chung ◽  
F. T. Leighton ◽  
Arnold L. Rosenberg

2019 ◽  
Vol 21 (12) ◽  
pp. 3573-3647 ◽  
Author(s):  
Felix Joos ◽  
Jaehoon Kim ◽  
Daniela Kühn ◽  
Deryk Osthus

2014 ◽  
Vol 162 ◽  
pp. 70-77 ◽  
Author(s):  
L. Alcón ◽  
M. Gutierrez ◽  
M.P. Mazzoleni

Algorithmica ◽  
2007 ◽  
Vol 54 (1) ◽  
pp. 89-106 ◽  
Author(s):  
Reuven Bar-Yehuda ◽  
Michael Beder ◽  
Yuval Cohen ◽  
Dror Rawitz

Author(s):  
Agelos Georgakopoulos ◽  
John Haslegrave ◽  
Thomas Sauerwald ◽  
John Sylvester

Abstract We apply the power-of-two-choices paradigm to a random walk on a graph: rather than moving to a uniform random neighbour at each step, a controller is allowed to choose from two independent uniform random neighbours. We prove that this allows the controller to significantly accelerate the hitting and cover times in several natural graph classes. In particular, we show that the cover time becomes linear in the number n of vertices on discrete tori and bounded degree trees, of order $${\mathcal O}(n\log \log n)$$ on bounded degree expanders, and of order $${\mathcal O}(n{(\log \log n)^2})$$ on the Erdős–Rényi random graph in a certain sparsely connected regime. We also consider the algorithmic question of computing an optimal strategy and prove a dichotomy in efficiency between computing strategies for hitting and cover times.


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