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In this short note we prove that every tournament contains the $k$-th power of a directed path of linear length. This improves upon recent results of Yuster and of Gir~ao. We also give a complete solution for this problem when $k=2$, showing that there is always a square of a directed path of length $lceil 2n/3 rceil-1$, which is best possible.
We consider a generalisation of Kellys conjecture which is due to Alspach, Mason, and Pullman from 1976. Kellys conjecture states that every regular tournament has an edge decomposition into Hamilton cycles, and this was proved by Kuhn and Osthus for
Given graphs $G$ and $H$ and a positive integer $q$ say that $G$ is $q$-Ramsey for $H$, denoted $Grightarrow (H)_q$, if every $q$-colouring of the edges of $G$ contains a monochromatic copy of $H$. The size-Ramsey number $hat{r}(H)$ of a graph $H$ is
Given a positive integer $s$, a graph $G$ is $s$-Ramsey for a graph $H$, denoted $Grightarrow (H)_s$, if every $s$-colouring of the edges of $G$ contains a monochromatic copy of $H$. The $s$-colour size-Ramsey number ${hat{r}}_s(H)$ of a graph $H$ is
In 1976, Alspach, Mason, and Pullman conjectured that any tournament $T$ of even order can be decomposed into exactly ${rm ex}(T)$ paths, where ${rm ex}(T):= frac{1}{2}sum_{vin V(T)}|d_T^+(v)-d_T^-(v)|$. We prove this conjecture for all sufficiently
We study the asymptotic behavior of the maximum number of directed cycles of a given length in a tournament: let $c(ell)$ be the limit of the ratio of the maximum number of cycles of length $ell$ in an $n$-vertex tournament and the expected number of