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20242026
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7 papers · 1 filter

math.CO2026

Global Product Intersection Sets in Semigroups

Wouter van Doorn, Pietro Monticone, Quanyu Tang

For a family of subsets of a semigroup, the product intersection set records those exponents for which the -fold product set of the intersect…

math.CO2026

On Spielman's Laplacian Eigenratio Conjecture and Related Problems

Jie Ma, Quanyu Tang, Yuchang Wang +1

Let be an -vertex graph with Laplacian eigenvalues . Motivated by the Alon-Boppana bound and the Ramanujan phenomenon for regular grap…

math.CO2026

Optimal bounds for an Erdős problem on matching integers to distinct multiples

Wouter van Doorn, Yanyang Li, Quanyu Tang

Let be the largest integer such that for every set of positive integers and every open interval of length , there exist at least $…

math.CO2026

An Erdős--Trotter problem on antichains with multiplicity on each occurring level

Yixin He, Quanyu Tang

Fix an integer . For each we consider families that form an antichain and have the property that, for every , if there exists $A\in\math…

math.CO2026

An Erdős problem on random subset sums in finite abelian groups

Jie Ma, Quanyu Tang

Let denote the least integer such that, if is an abelian group of order and is a uniformly random -element subset, then with probability at le…

math.CO2026

On the maximum product of distances of diameter point sets

Stijn Cambie, Arne Decadt, Yanni Dong +2

We consider a problem posed by Erdős, Herzog and Piranian on the maximum product of distances of a point set of order with a given diameter. We prove that it is sufficient to c…

math.CO2026

Largest Sidon subsets in weak Sidon sets

Jie Ma, Quanyu Tang

A finite set is called a Sidon set if all sums with and are distinct, and a weak Sidon set if all sums with $ x,y…