Lei Yu

activity

20172020

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Showing math.COShow all

4 papers · 1 filter

math.CO2020

Exact minimum codegree thresholds for $K_{4}^{-}$ -covering and $K_{5}^{-}$ -covering

Lei Yu, Xinmin Hou, Boyuan Liu +1

Given two $3$ -graphs $F$ and $H$ , an $F$ -covering of $H$ is a collection of copies of $F$ in $H$ such that each vertex of $H$ is contained in at least one copy of them. Let {$c_2(n…

math.CO2018

Codegree threshold for tiling $k$ -graphs with two edges sharing exactly $ℓ$ vertices

Lei Yu, Xinmin Hou

Given integer $k$ and a $k$ -graph $F$ , let $t_{k - 1} (n, F)$ be the minimum integer $t$ such that every $k$ -graph $H$ on $n$ vertices with codegree at least $t$ contains an $F$ -factor…

math.CO2017

The size of $3$ -uniform hypergraphs with given matching number and codegree

Xinmin Hou, Lei Yu, Jun Gao +1

Determine the size of $r$ -graphs with given graph parameters is an interesting problem. Chvátal and Hanson (JCTB, 1976) gave a tight upper bound of the size of 2-graphs with restri…

math.CO2017

Odd induced subgraphs in graphs with treewidth at most two

Xinmin Hou, Lei Yu, Jiaao Li +1

A long-standing conjecture asserts that there exists a constant $c > 0$ such that every graph of order $n$ without isolated vertices contains an induced subgraph of order at least $c…

Exact minimum codegree thresholds for K4−​-covering and K5−​-covering

Codegree threshold for tiling k-graphs with two edges sharing exactly ℓ vertices

The size of 3-uniform hypergraphs with given matching number and codegree

Odd induced subgraphs in graphs with treewidth at most two

Exact minimum codegree thresholds for $K_{4}^{-}$ -covering and $K_{5}^{-}$ -covering

Codegree threshold for tiling $k$ -graphs with two edges sharing exactly $ℓ$ vertices

The size of $3$ -uniform hypergraphs with given matching number and codegree