activity
20132026
most citedIntroduction to the combinatorial atlas

13 citations · 113 across the 34 of their papers we have counts for

collaborators

36 papers

math.CO2026

Breaking the Infinite Barrier in the -- Conjecture

Max Aires, Swee Hong Chan, Igor Pak +1

The balance constant is a poset parameter measuring how well random linear extensions can be split according to their relative order on two elements. We give an -impro…

math.CO2026

Equality conditions for correlation inequalities

Swee Hong Chan, Igor Pak

We prove equality conditions for the Ahlswede--Daykin (AD) inequality and the Fortuin--Kasteleyn--Ginibre (FKG) inequality. We then present a number of applications and special cas…

math.CO2026

Correlation inequalities for Schur positivity

Swee Hong Chan, Hong Chen, Igor Pak +1

We generalize the Ahlswede--Daykin inequality (1978) to a Schur positive \emph{ADS inequality}, which also contains the Lam--Postnikov--Pylyavskyy inequality (2007) as a special ca…

math.CO2026

Independent Sets and Continued Fractions

Swee Hong Chan, Steven Heilman, Greta Panova

Linek's 1989 problem asks whether the numbers of independent sets of trees avoid infinitely many positive integers. We show that the set of natural numbers realized as the number o…

math.PR2025

Normalized matching property for competing urn models

Swee Hong Chan

We study the competing urn model in which balls are placed independently into urns according to (possibly distinct) ball distributions. Kahn and Neiman (2010) showed that,…

math.CO2025

Unimodality for Radon partitions of random vectors

Swee Hong Chan, Gil Kalai, Bhargav Narayanan +2

Consider the (almost surely) unique Radon partition of a set of random Gaussian vectors in ; choose one of the two parts of this partition uniformly at random,…

math.CO2025

Effective resistance in planar graphs and continued fractions

Swee Hong Chan, Alex Kontorovich, Igor Pak

For a simple graph and edge , the effective resistance is defined as a ratio , where denotes the number of spanning trees in . We r…

math.CO2024

Spanning trees and continued fractions

Swee Hong Chan, Alex Kontorovich, Igor Pak

We prove the exponential growth of the cardinality of the set of numbers of spanning trees in simple (and planar) graphs on vertices, answering a question of Sedláček from 1969…

math.CO2024

Equality cases of the Stanley--Yan log-concave matroid inequality

Swee Hong Chan, Igor Pak

The \emph{Stanley--Yan} (SY) \emph{inequality} gives the ultra-log-concavity for the numbers of bases of a matroid which have given sizes of intersections with fixed disjoint s…

math.CO2024★ 3 cited

Linear extensions and continued fractions

Swee Hong Chan, Igor Pak

We introduce several new constructions of finite posets with the number of linear extensions given by generalized continued fractions. We apply our results to the problem of the mi…

math.CO2023★ 3 cited

Linear extensions of finite posets

Swee Hong Chan, Igor Pak

We give a broad survey of inequalities for the number of linear extensions of finite posets. We review many examples, discuss open problems, and present recent results on the subje…

math.CO2023★ 8 cited

Equality cases of the Alexandrov--Fenchel inequality are not in the polynomial hierarchy

Swee Hong Chan, Igor Pak

Describing the equality conditions of the Alexandrov--Fenchel inequality has been a major open problem for decades. We prove that in the case of convex polytopes, this description…

math.CO2023★ 2 cited

Computational complexity of counting coincidences

Swee Hong Chan, Igor Pak

Can you decide if there is a coincidence in the numbers counting two different combinatorial objects? For example, can you decide if two regions in have the same num…

math.CO2023★ 2 cited

On the cross-product conjecture for the number of linear extensions

Swee Hong Chan, Igor Pak, Greta Panova

We prove a weak version of the cross--product conjecture: , where is the number of…

math.CO2022★ 5 cited

Multivariate correlation inequalities for -partitions

Swee Hong Chan, Igor Pak

Motivated by the Lam--Pylyavskyy inequalities for Schur functions, we give a far reaching multivariate generalization of Fishburn's correlation inequality for the number of linear…

math.CO2022★ 1 cited

Correlation inequalities for linear extensions

Swee Hong Chan, Igor Pak

We employ the combinatorial atlas technology to prove new correlation inequalities for the number of linear extensions of finite posets. These include the approximate independence…

math.CO2022★ 7 cited

Effective poset inequalities

Swee Hong Chan, Igor Pak, Greta Panova

We explore inequalities on linear extensions of posets and make them effective in different ways. First, we study the Björner--Wachs inequality and generalize it to inequalities on…

math.CO2022★ 13 cited

Introduction to the combinatorial atlas

Swee Hong Chan, Igor Pak

We give elementary self-contained proofs of the strong Mason conjecture recently proved by Anari at. al. (arXiv:1811.01600) and Brändén--Huh (arXiv:1902.03719), and of the classica…

math.CO2021★ 5 cited

Log-concave poset inequalities

Swee Hong Chan, Igor Pak

We study combinatorial inequalities for various classes of set systems: matroids, polymatroids, poset antimatroids, and interval greedoids. We prove log-concavity inequalities for…

math.CO2021★ 2 cited

Log-concavity in planar random walks

Swee Hong Chan, Igor Pak, Greta Panova

We prove log-concavity of exit probabilities of lattice random walks in certain planar regions.

math.CO2021★ 12 cited

Extensions of the Kahn--Saks inequality for posets of width two

Swee Hong Chan, Igor Pak, Greta Panova

The Kahn--Saks inequality is a classical result on the number of linear extensions of finite posets. We give a new proof of this inequality for posets of width two using explicit i…

math.CO2021★ 9 cited

The cross-product conjecture for width two posets

Swee Hong Chan, Igor Pak, Greta Panova

The cross--product conjecture (CPC) of Brightwell, Felsner and Trotter (1995) is a two-parameter quadratic inequality for the number of linear extensions of a poset …

math.PR2020★ 1 cited

Recurrence of horizontal-vertical walks

Swee Hong Chan

Consider a nearest neighbor random walk on the two-dimensional integer lattice, where each vertex is initially labeled either `H' or `V', uniformly and independently. At each discr…

math.CO2020★ 3 cited

Sorting probability of Catalan posets

Swee Hong Chan, Igor Pak, Greta Panova

We show that the sorting probability of the Catalan poset} satisfies .