Jiaxi Nie

activity

20202026

most citedTriangle-free Subgraphs of Hypergraphs

4 citations · 8 across the 23 of their papers we have counts for

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28 papers · 1 filter

math.CO2026

Block Designs with Large Transversal-Block Intersections

Jiaxi Nie

A block design is a set family, whose members are called blocks, where every pair of points in the universe is covered by exactly one block. Erdős asked the following question: is…

math.CO2026

Matching and intersection problems for non-trivial $r$ -partite $r$ -uniform hypergraphs

Peter Frankl, Jiaxi Nie

A central theme in extremal combinatorics is the study of the maximum number of edges in an $r$ -uniform hypergraph ( $r$ -graph) with matching number at most $s$ (the Erdős Matching…

math.CO2026

Hypergraph Ramsey numbers with quasipolynomial growth rate

Xiaoyu He, Jiaxi Nie, Logan Post +1

For a 3-uniform hypergraph (3-graph) $F$ , let $r (F, n)$ be the smallest $N$ such that any $N$ -vertex $F$ -free 3-graph has an independent set of size $n$ . We construct a $3$ -graph $H…

math.CO2025

Decomposition of Cliques into $k$ -Star-Forests

Jiaxi Nie, Yibo Ren, Hehui Wu

A $k$ -star-forest is a forest with at most $k$ connected components where each component is a star. Let $F_{k} (n)$ be the minimum integer such that the complete graph on $n$ vertices…

math.CO2025

Maximum in-general-position set in a random subset of $F_{q}^{d}$

Yaobin Chen, Jiaxi Nie, Jing Yu +1

Let $α (F_{q}^{d}, p)$ be the maximum possible size of a point set in general position in a $p$ -random subset of $F_{q}^{d}$ . We determine the order of magnitude of $α(\m…

math.CO2025

Evasive sets, twisted varieties, and container-clique trees

Jeck Lim, Jiaxi Nie, Ji Zeng

In the affine space $F_{q}^{n}$ over the finite field of order $q$ , a point set $S$ is said to be $(d, k, r)$ -evasive if the intersection between $S$ and any variety, of dimensi…

math.CO2025

Off-Diagonal Ramsey Numbers for Linear Hypergraphs

Xiaoyu He, Jiaxi Nie, Yuval Wigderson +1

We study off-diagonal Ramsey numbers $r (H, K_{n}^{(k)})$ of $k$ -uniform hypergraphs, where $H$ is a fixed linear $k$ -uniform hypergraph and $K_{n}^{(k)}$ is complete on $n$ vertices. R…

math.CO2025

Supersaturation of odd linear cycles

Lirong Deng, Jie Han, Jiaxi Nie +1

An $r$ -uniform linear cycle of length $ℓ$ , denoted by $C_{ℓ}^{r}$ , is an $r$ -graph with $ℓ$ edges $e_{1}, e_{2}, \dots, e_{ℓ}$ where $e_i=\{v_{(r-1)(i-1)},v_{(r-1)(i-1)+1},\dots…

math.CO2025

Generalized Erdős-Rogers problems for hypergraphs

Xiaoyu He, Jiaxi Nie

Given $r$ -uniform hypergraphs $G$ and $F$ and an integer $n$ , let $f_{F, G} (n)$ be the maximum $m$ such that every $n$ -vertex $G$ -free $r$ -graph has an $F$ -free induced subgraph on…

math.CO2024

On tight tree-complete hypergraph Ramsey numbers

Jiaxi Nie

Chvátal showed that for any tree $T$ with $k$ edges the Ramsey number $R (T, n) = k (n - 1) + 1$ ("Tree-complete graph Ramsey numbers." Journal of Graph Theory 1.1 (1977): 93-93). For $r = 3$ …

math.CO2024

Random Turán Problems for $K_{s, t}$ Expansions

Jiaxi Nie, Sam Spiro

Let $K_{s, t}^{(r)}$ denote the $r$ -uniform hypergraph obtained from the graph $K_{s, t}$ by inserting $r - 2$ new vertices inside each edge of $K_{s, t}$ . We prove essentially tight bo…

math.CO2024

On the Matching Problem in Random Hypergraphs

Peter Frankl, Jiaxi Nie, Jian Wang

We study a variant of the Erdős Matching Problem in random hypergraphs. Let $K_{p} (n, k)$ denote the Erdős-Rényi random $k$ -uniform hypergraph on $n$ vertices where each pos…

math.CO2024

Off-diagonal Ramsey numbers for slowly growing hypergraphs

Sam Mattheus, Dhruv Mubayi, Jiaxi Nie +1

For a $k$ -uniform hypergraph $F$ and a positive integer $n$ , the Ramsey number $r (F, n)$ denotes the minimum $N$ such that every $N$ -vertex $F$ -free $k$ -uniform hypergraph contains…

math.CO2024

On odd covers of cliques and disjoint unions

Calum Buchanan, Alexander Clifton, Eric Culver +5

Babai and Frankl posed the ``odd cover problem" of finding the minimum cardinality of a collection of complete bipartite graphs such that every edge of the complete graph of order…

math.CO2024

Random Turán Problems for Hypergraph Expansions

Jiaxi Nie, Sam Spiro

Given an $r_{0}$ -uniform hypergraph $F$ , we define its $r$ -uniform expansion $F^{(r)}$ to be the hypergraph obtained from $F$ by inserting $r - r_{0}$ distinct vertices into each edge of…

math.CO2023

Sidorenko Hypergraphs and Random Turán Numbers

Jiaxi Nie, Sam Spiro

Let $ex (G_{n, p}^{r}, F)$ denote the maximum number of edges in an $F$ -free subgraph of the random $r$ -uniform hypergraph $G_{n, p}^{r}$ , and let $s(F):=\sup\{s: \exists H,\ t_F(…

math.CO2023

Random Turán and counting results for general position sets over finite fields

Yaobin Chen, Xizhi Liu, Jiaxi Nie +1

Let $α (F_{q}^{d}, p)$ denote the maximum size of a general position set in a $p$ -random subset of $F_{q}^{d}$ . We determine the order of magnitude of $α (F_{q}^{2}, p)$ …

math.CO2023

Random Turán theorem for expansions of spanning subgraphs of tight trees

Jiaxi Nie

The $r$ -expansion of a $k$ -uniform hypergraph $H$ , denoted by $H^{(+ r)}$ , is an $r$ -uniform hypergraph obtained by enlarging each $k$ -edge of $H$ with a set of $r - k$ vertices of de…

math.CO2023

Turán theorems for even cycles in random hypergraph

Jiaxi Nie

Let $F$ be a family of $r$ -uniform hypergraphs. The random Turán number $ex (G_{n, p}^{r}, F)$ is the maximum number of edges in an $F$ -free subgr…

math.CO2023

On asymptotic local Turán problems

Peter Frankl, Jiaxi Nie

An $r$ -uniform hypergraph has $(q, p)$ -property if any set of $q$ vertices spans a complete sub-hypergraph on $p$ vertices. Let $t_{r} (n, q, p)$ be the minimum edge density of an $n$ -ve…

math.CO2022

On asymptotic packing of convex geometric and ordered graphs

Jiaxi Nie, Erlang Surya, Ji Zeng

A convex geometric graph $G$ is said to be packable if there exist edge-disjoint copies of $G$ in the complete convex geometric graph $K_{n}$ covering all but $o (n^{2})$ edges. We prov…

math.CO2022★ 1 cited

On Turán numbers for disconnected hypergraphs

Raffaella Mulas, Jiaxi Nie

We introduce the following simpler variant of the Turán problem: Given integers $n > k > r \geq 2$ and $m \geq 1$ , what is the smallest integer $t$ for which there exists an $r$ -uniform…

math.CO2022

Odd Covers of Graphs

Calum Buchanan, Alexander Clifton, Eric Culver +4

Given a finite simple graph $G$ , an odd cover of $G$ is a collection of complete bipartite graphs, or bicliques, in which each edge of $G$ appears in an odd number of bicliques and…

math.CO2021

On Asymptotic Packing of Geometric Graphs

Daniel W. Cranston, Jiaxi Nie, Jacques Verstraëte +1

A set of geometric graphs is {\em geometric-packable} if it can be asymptotically packed into every sequence of drawings of the complete graph $K_{n}$ . For example, the set of geomet…

Block Designs with Large Transversal-Block Intersections

Matching and intersection problems for non-trivial r-partite r-uniform hypergraphs

Hypergraph Ramsey numbers with quasipolynomial growth rate

Decomposition of Cliques into k-Star-Forests

Maximum in-general-position set in a random subset of Fqd​

Evasive sets, twisted varieties, and container-clique trees

Off-Diagonal Ramsey Numbers for Linear Hypergraphs

Supersaturation of odd linear cycles

Generalized Erdős-Rogers problems for hypergraphs

On tight tree-complete hypergraph Ramsey numbers

Random Turán Problems for Ks,t​ Expansions

On the Matching Problem in Random Hypergraphs

Off-diagonal Ramsey numbers for slowly growing hypergraphs

On odd covers of cliques and disjoint unions

Random Turán Problems for Hypergraph Expansions

Sidorenko Hypergraphs and Random Turán Numbers

Random Turán and counting results for general position sets over finite fields

Random Turán theorem for expansions of spanning subgraphs of tight trees

Turán theorems for even cycles in random hypergraph

On asymptotic local Turán problems

On asymptotic packing of convex geometric and ordered graphs

On Turán numbers for disconnected hypergraphs

Odd Covers of Graphs

On Asymptotic Packing of Geometric Graphs

Matching and intersection problems for non-trivial $r$ -partite $r$ -uniform hypergraphs

Decomposition of Cliques into $k$ -Star-Forests

Maximum in-general-position set in a random subset of $F_{q}^{d}$

Random Turán Problems for $K_{s, t}$ Expansions