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Related papers: $(s,t)$-cores: a weighted version of Armstrong's c…

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Fix coprime $s,t\ge1$. We re-prove, without Ehrhart reciprocity, a conjecture of Armstrong (recently verified by Johnson) that the finitely many simultaneous $(s,t)$-cores have average size $\frac{1}{24}(s-1)(t-1)(s+t+1)$, and that the…

Combinatorics · Mathematics 2023-04-21 Victor Y. Wang

Armstrong, Hanusa and Jones conjectured that if $s,t$ are coprime integers, then the average size of an $(s,t)$-core partition and the average size of a self-conjugate $(s,t)$-core partition are both equal to $\frac{(s+t+1)(s-1)(t-1)}{24}$.…

Combinatorics · Mathematics 2014-05-12 William Y. C. Chen , Harry H. Y. Huang , Larry X. W. Wang

A beautiful recent conjecture of D. Armstrong predicts the average size of a partition that is simultaneously an $s$-core and a $t$-core, where $s$ and $t$ are coprime. Our goal is to prove this conjecture when $t=s+1$. These simultaneous…

Combinatorics · Mathematics 2015-04-03 Richard P. Stanley , Fabrizio Zanello

Johnson recently proved Armstrong's conjecture which states that the average size of an $(a,b)$-core partition is $(a+b+1)(a-1)(b-1)/24$. He used various coordinate changes and one-to-one correspondences that are useful for counting…

Combinatorics · Mathematics 2017-11-07 Jineon Baek , Hayan Nam , Myungjun Yu

A conjecture of Armstrong states that if $\gcd (a, b) = 1$, then the average size of an $(a, b)$-core partition is $(a - 1)(b - 1)(a + b + 1) / 24$. Recently, Stanley and Zanello used a recursive argument to verify this conjecture when $a =…

Combinatorics · Mathematics 2015-02-09 Amol Aggarwal

Simultaneous core partitions have been widely studied in the past 20 years. In 2013, Amdeberhan gave several conjectures on the number, the average size, and the largest size of $(t,t+1)$-core partitions with distinct parts, which was…

Combinatorics · Mathematics 2025-03-04 Huan Xiong , Lihong Yang

Simultaneous core partitions are important objects in algebraic combinatorics. Recently there has been interest in studying the distribution of sizes among all $(s,t)$-cores for coprime $s$ and $t$. Zaleski (2017) gave strong evidence that…

Combinatorics · Mathematics 2018-09-05 János Komlós , Emily Sergel , Gábor Tusnády

Suppose $s$ and $t$ are coprime natural numbers. A theorem of Olsson says that the $t$-core of an $s$-core partition is again an $s$-core. We generalise this theorem, showing that the $s$-weight of the $t$-core of a partition $\lambda$ is…

Combinatorics · Mathematics 2014-05-14 Matthew Fayers

Motivated by Amdeberhan's conjecture on $(t,t+1)$-core partitions with distinct parts, various results on the numbers, the largest sizes and the average sizes of simultaneous core partitions with distinct parts were obtained by many…

Combinatorics · Mathematics 2017-09-05 Huan Xiong

A conjecture on the monotonicity of t-core partitions in an article of Stanton [Open positivity conjectures for integer partitions, Trends Math., 2:19-25, 1999] has been the catalyst for much recent research on t-core partitions. We…

Number Theory · Mathematics 2015-03-20 Christopher R. H. Hanusa , Rishi Nath

We observe that for a and b relatively prime, the "abacus construction" identifies the set of simultaneous (a,b)-core partitions with lattice points in a rational simplex. Furthermore, many statistics on (a,b)-cores are piecewise polynomial…

Combinatorics · Mathematics 2015-06-24 Paul Johnson

Jaclyn Anderson proved that if s and t are relatively prime positive integers, then there are exactly (s+t-1)!/(s!t!) partitions whose set of hook-lengths is disjoint from the set {s,t}. Drew Armstrong conjectured (and Paul Johnson, and a…

Combinatorics · Mathematics 2015-09-03 Shalosh B. Ekhad , Doron Zeilberger

A tremendous amount of research has been done in the last two decades on $(s,t)$-core partitions when $s$ and $t$ are positive integers with no common divisor. Here we change perspective slightly and explore properties of $(s,t)$-core and…

Combinatorics · Mathematics 2024-05-31 Jean-Baptiste Gramain , Rishi Nath , James A. Sellers

In 2016, Nath and Sellers proposed a conjecture regarding the precise largest size of ${(s,ms-1,ms+1)}$-core partitions. In this paper, we prove their conjecture. One of the key techniques in our proof is to introduce and study the…

Combinatorics · Mathematics 2024-03-06 Yetong Sha , Huan Xiong

Fix $t \geq 2$. We first give an asymptotic formula for certain sums of the number of $t$-cores. We then use this result to compute the distribution of the size of the $t$-core of a uniformly random partition of an integer $n$. We show that…

Probability · Mathematics 2023-02-28 Arvind Ayyer , Shubham Sinha

In this paper we prove that Amdeberhan's conjecture on the largest size of $(t, t+1, t+2)$-core partitions is true. We also show that the number of $(t, t + 1, t + 2)$-core partitions with the largest size is $1$ or $2$ based on the parity…

Combinatorics · Mathematics 2015-01-08 Huan Xiong

Simultaneous core partitions have attracted much attention since Anderson's work on the number of $(t_1,t_2)$-core partitions. In this paper we focus on simultaneous core partitions with distinct parts. The generating function of $t$-core…

Combinatorics · Mathematics 2017-03-21 Huan Xiong

We consider simultaneous $(s,s+t,s+2t,\dots,s+pt)$-core partitions in the large-$p$ limit, or (when $s<t$), partitions in which no hook may be of length $s \pmod{t}$. We study generating functions, containment properties, and congruences…

Combinatorics · Mathematics 2025-12-18 William Keith , Rishi Nath , James Sellers

For a positive integer $t \geq 2$, the $t$-core of a partition plays an important role in modular representation theory and combinatorics. We initiate the study of $t$-cores of partitions contained in an $r \times s$ rectangle. Our main…

Combinatorics · Mathematics 2024-04-30 Arvind Ayyer , Shubham Sinha

Anderson established a connection between core partitions and order ideals of certain posets by mapping a partition to its $\beta$-set. In this paper, we give a characterization of the poset $P_{(s,s+1,s+2)}$ whose order ideals correspond…

Combinatorics · Mathematics 2014-07-10 Jane Y. X. Yang , Michael X. X. Zhong , Robin D. P. Zhou
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