论文标题

Ramsey在随机图中的树木善良

Ramsey goodness of trees in random graphs

论文作者

Araújo, Pedro, Moreira, Luiz, Pavez-Signé, Matías

论文摘要

对于图$ g $,我们编写$ g \ rightarrow \ big(k_ {r+1},\ Mathcal {t}(t}(n,n,d)\ big)$,如果$ g $的每种蓝色的颜色包含$ k_ {r+1} $的蓝色副本,或者是每种$ n $ n $ ed $ edges的蓝色副本,则最多可达$ dgges $ dd $ dd $ dd $ dd $ dd $ dd $ dd $ dd $ d。 1977年,Chvátal证明,对于任何整数,$ r,n,d \ ge 2 $,$ k_n \ rightarrow \ big(k_ {r+1},\ mathcal {t}(t}(n,n,d)\ big)$,则仅在$ n \ ge rn+1 $中。我们证明了chvátal的定理的随机模拟,也就是说,我们表明,对于每个$ r,d \ ge 2 $,存在常数$ c,c'> 0 $,以便如果$ p \ ge c {n}^{ - 2/(2/(r + 2)} $和$ n \ geq rn + c rn + c'/p $,n,然后\ big(k_ {r+1},\ Mathcal {t}(n,d)\ big)\] \] \] \ highosigation $ n \ to \ infty $。该证明将稳定性参数与树木图中的树木嵌入结合在一起。此外,稳定性结果的证明是基于erdős-s-Sós的稀疏随机类似物,这些猜想是线性尺寸和有界最大程度的树木,这可能具有独立的关注。

For a graph $G$, we write $G\rightarrow \big(K_{r+1},\mathcal{T}(n,D)\big)$ if every blue-red colouring of the edges of $G$ contains either a blue copy of $K_{r+1}$, or a red copy of each tree with $n$ edges and maximum degree at most $D$. In 1977, Chvátal proved that for any integers $r,n,D \ge 2$, $K_N \rightarrow \big(K_{r+1},\mathcal{T}(n,D)\big)$ if and only if $N \ge rn+1$. We prove a random analogue of Chvátal's theorem for bounded degree trees, that is, we show that for each $r,D\ge 2$ there exist constants $C,C'>0$ such that if $p \ge C{n}^{-2/(r+2)}$ and $N \geq rn + C'/p$, then \[G(N,p) \rightarrow \big(K_{r+1},\mathcal{T}(n,D)\big)\] with high probability as $n\to \infty$. The proof combines a stability argument with the embedding of trees in expander graphs. Furthermore, the proof of the stability result is based on a sparse random analogue of the Erdős--Sós conjecture for trees with linear size and bounded maximum degree, which may be of independent interest.

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