Works (23)

Updated: July 5th, 2023 15:39

2021 journal article

Channels, Billiards, and Perfect Matching 2-Divisibility

ELECTRONIC JOURNAL OF COMBINATORICS, 28(2).

By: G. Barkley n & R. Liu n

TL;DR: A new combinatorial proof of Lovász's result that the existence of a nontrivial channel is equivalent to $m_G$ being even is given and it is strengthened by showing that the number of channels gives a lower bound on the power of 2 dividing m_G when $G$ is planar. (via Semantic Scholar)
Source: Web Of Science
Added: July 19, 2021

2021 article

Determinantal Formulas for SEM Expansions of Schubert Polynomials

Hatam, H., Johnson, J., Liu, R. I., & Macaulay, M. (2021, October 23). ANNALS OF COMBINATORICS.

By: H. Hatam n, J. Johnson n, R. Liu* & M. Macaulay n

Source: Web Of Science
Added: November 8, 2021

2021 journal article

P-Partitions and Quasisymmetric Power Sums

INTERNATIONAL MATHEMATICS RESEARCH NOTICES, 2021(18), 13975–14015.

By: R. Liu n & M. Weselcouch n

UN Sustainable Development Goal Categories
4. Quality Education (Web of Science)
Source: Web Of Science
Added: January 3, 2022

2021 journal article

Up- and Down-operators on Young's Lattice

ELECTRONIC JOURNAL OF COMBINATORICS, 28(3).

By: R. Liu n & C. Smith n

Source: Web Of Science
Added: August 23, 2021

2020 journal article

P-partition generating function equivalence of naturally labeled posets

JOURNAL OF COMBINATORIAL THEORY SERIES A, 170.

By: R. Liu n & M. Weselcouch n

author keywords: P-Partition; Quasisymmetric function; Combinatorial hopf algebra
TL;DR: Using the Hopf algebra of posets, necessary conditions for two posets to have the same generating function are given and it is shown that they must have the the same number of antichains of each size, as well as the same shape. (via Semantic Scholar)
UN Sustainable Development Goal Categories
4. Quality Education (Web of Science)
Source: Web Of Science
Added: November 18, 2019

2020 journal article

The algebra of Schur operators

EUROPEAN JOURNAL OF COMBINATORICS, 87.

By: R. Liu n & C. Smith n

TL;DR: A representation of the (local) plactic monoid given by Schur operators, which act on partitions by adding a box in column $i$ (if possible) is studied. (via Semantic Scholar)
Source: Web Of Science
Added: May 26, 2020

2019 journal article

Flow Polytopes and the Space of Diagonal Harmonics

Canadian Journal of Mathematics, 1–27.

By: R. Liu n, A. Morales n & K. Mészáros n

author keywords: flow polytope; threshold graph; diagonal harmonic; Tesler matrix
Source: Crossref
Added: July 28, 2019

2019 journal article

GELFAND-TSETLIN POLYTOPES: A STORY OF FLOW AND ORDER POLYTOPES

SIAM JOURNAL ON DISCRETE MATHEMATICS, 33(4), 2394–2415.

By: R. Liu*, K. Meszaros & A. St Dizier

TL;DR: Corollaries are drawn from the result that the number of integer points of the Gelfand-Tsetlin polytope is equal to the dimension of the corresponding irreducible representation ofGL(n)$. (via Semantic Scholar)
Source: Web Of Science
Added: June 29, 2020

2018 journal article

Kronecker coefficients and noncommutative super Schur functions

Journal of Combinatorial Theory, Series A, 158, 315–361.

By: J. Blasiak* & R. Liu n

author keywords: Kronecker coefficients; Noncommutative Schur functions; Super Schur functions; Colored tableaux
TL;DR: A theory of noncommutative super Schur functions is developed and used to prove a positive combinatorial rule for the Kronecker coefficients where one of the partitions is a hook, recovering previous results of the two authors. (via Semantic Scholar)
Sources: Web Of Science, Crossref
Added: August 6, 2018

2017 journal article

A simplified Kronecker rule for one hook shape

Proceedings of the American Mathematical Society, 145(9), 3657–3664.

By: R. Liu n

Source: Crossref
Added: July 28, 2019

2016 journal article

Complete branching rules for Specht modules

JOURNAL OF ALGEBRA, 446, 77–102.

By: R. Liu n

author keywords: Symmetric group; Specht modules; Branching rule
UN Sustainable Development Goal Categories
15. Life on Land (OpenAlex)
Source: Web Of Science
Added: August 6, 2018

2016 journal article

On the commutative quotient of Fomin-Kirillov algebras

EUROPEAN JOURNAL OF COMBINATORICS, 54, 65–75.

By: R. Liu n

TL;DR: The Fomin-Kirillov algebra E n is a noncommutative algebra with a generator for each edge of the complete graph on n vertices and the commutative quotient of E G is isomorphic to the Orlik-Terao algebra of G. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2016 journal article

Subalgebras of the Fomin-Kirillov algebra

JOURNAL OF ALGEBRAIC COMBINATORICS, 44(3), 785–829.

By: J. Blasiak*, R. Liu n & K. Meszaros*

author keywords: Fomin-Kirillov algebra; Coxeter group; nil-Coxeter algebra; Nichols algebra
Source: Web Of Science
Added: August 6, 2018

2015 journal article

Positive expressions for skew divided difference operators

JOURNAL OF ALGEBRAIC COMBINATORICS, 42(3), 861–874.

By: R. Liu n

author keywords: Skew divided difference operator; Fomin-Kirillov algebra; Braided Hopf algebra; Bruhat order
Source: Web Of Science
Added: August 6, 2018

2014 journal article

Coefficients of a relative of cyclotomic polynomials

Acta Arithmetica, 165(4), 301–325.

By: R. Liu*

author keywords: cyclotomic polynomial; height
Source: Crossref
Added: July 28, 2019

2014 journal article

Laurent polynomials, Eulerian numbers, and Bernstein's theorem

Journal of Combinatorial Theory, Series A, 124, 244–250.

By: R. Liu*

author keywords: Eulerian number; Bernstein's theorem; Hypersimplex
TL;DR: It is shown that a refinement of Eulerian numbers gives a combinatorial interpretation for volumes of certain rational hyperplane sections of the hypercube. (via Semantic Scholar)
Source: Crossref
Added: July 28, 2019

2013 journal article

Nonconvexity of the set of hypergraph degree sequences

Electronic Journal of Combinatorics, 20(1).

By: R. Liu

Source: NC State University Libraries
Added: July 28, 2019

2012 journal article

Matching polytopes and Specht modules

Transactions of the American Mathematical Society, 364(2), 1089–1107.

By: R. Liu*

UN Sustainable Development Goal Categories
15. Life on Land (OpenAlex)
Source: Crossref
Added: July 28, 2019

2011 journal article

Matrices with restricted entries and $q$-analogues of permutations

Journal of Combinatorics, 2(3), 355–395.

By: J. Lewis*, R. Liu*, A. Morales*, G. Panova*, S. Sam* & Y. Zhang*

Source: Crossref
Added: July 28, 2019

2010 journal article

An algorithmic Littlewood-Richardson rule

Journal of Algebraic Combinatorics, 31(2), 253–266.

By: R. Liu*

author keywords: Littlewood-Richardson rule; Specht modules; Grassmannian
Source: Crossref
Added: July 28, 2019

2010 thesis

Specht modules and Schubert varieties for general diagrams

(PhD Thesis). http://hdl.handle.net/1721.1/60196.

By: R. Liu

Source: NC State University Libraries
Added: July 10, 2019

2007 journal article

Counting subrings of <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msup><mml:mi mathvariant="double-struck">Z</mml:mi><mml:mi>n</mml:mi></mml:msup></mml:math> of index k

Journal of Combinatorial Theory, Series A, 114(2), 278–299.

By: R. Liu*

author keywords: subrings; lattices; multiplicative lattices
TL;DR: This work considers the problem of determining the number of subrings of the ring Z^n of a fixed index k, denoted f"n(k) and presents a decomposition theorem for these subrings and calculates explicit expressions for the Dirichlet series generating function. (via Semantic Scholar)
Source: Crossref
Added: October 30, 2020

2007 journal article

Counting subrings of Zn of index k

Journal of Combinatorial Theory Series A, 114(2), 278–299.

By: R. Liu

Source: NC State University Libraries
Added: July 28, 2019

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