Colin Defant

activity

20152026

most citedOn the Density of Ranges of Generalized Divisor Functions

6 citations · 25 across the 32 of their papers we have counts for

collaborators

Showing 2020 · math.COShow all

9 papers · 2 filters

math.CO2020

Highly Sorted Permutations and Bell Numbers

Colin Defant

Let $s$ denote West's stack-sorting map. For all positive integers $m$ and all integers $n \geq 2 m - 2$ , we give a simple characterization of the set $s^{n - m} (S_{n})$ ; as a consequence,…

math.CO2020

Asymptotics of 3-stack-sortable permutations

Colin Defant, Andrew Elvey Price, Anthony J Guttmann

We derive a simple functional equation with two catalytic variables characterising the generating function of 3-stack-sortable permutations. Using this functional equation, we exte…

math.CO2020

Typical and Extremal Aspects of Friends-and-Strangers Graphs

Noga Alon, Colin Defant, Noah Kravitz

Given graphs $X$ and $Y$ with vertex sets $V (X)$ and $V (Y)$ of the same cardinality, the friends-and-strangers graph $FS (X, Y)$ is the graph whose vertex set consists of al…

math.CO2020

Friends and Strangers Walking on Graphs

Colin Defant, Noah Kravitz

Given graphs $X$ and $Y$ with vertex sets $V (X)$ and $V (Y)$ of the same cardinality, we define a graph $FS (X, Y)$ whose vertex set consists of all bijections $σ:V(X)\to V(Y…

math.CO2020

Stack-Sorting with Consecutive-Pattern-Avoiding Stacks

Colin Defant, Kai Zheng

We introduce consecutive-pattern-avoiding stack-sorting maps $SC_{σ}$ , which are natural generalizations of West's stack-sorting map $s$ and natural analogues of the classical…

math.CO2020★ 2 cited

Promotion Sorting

Colin Defant, Noah Kravitz

Schützenberger's promotion operator is an extensively-studied bijection that permutes the linear extensions of a finite poset. We introduce a natural extension $\partial$ of this o…