Electronic Journal of Combinatorics  

Maciej Bendkowski, Olivier Bodini, Sergey Dovgal

We present a quantitative, statistical analysis of random lambda terms in the De Bruijn notation. Following an analytic approach using multivariate generating functions, we investigate the distribution of various combinatorial parameters of random open an... see more

Alan Lew

Sam Spiro

Colin Cooper, Alan Frieze, Wesley Pegden

Emanuele Delucchi, Noriane Girard, Giovanni Paolini

We prove that the posets of connected components of intersections of toric and elliptic arrangements defined by root systems are EL-shellable and we compute their homotopy type. Our method rests on Bibby's description of such posets by means of "labeled p... see more

Svetlana Puzynina

Per Alexandersson, Svante Linusson, Samu Potka

Min Yan

We develop the theory of simple pentagonal subdivision of quadrilateral tilings, on orientable as well as non-orientable surfaces. Then we apply the theory to answer questions related to pentagonal tilings of surfaces, especially those related to pentagon... see more

Thomas Budzinski, Nicolas Curien, Bram Petri

Pierre Aboulker, Marthe Bonamy, Nicolas Bousquet, Louis Esperet

Zachary Gershkoff, James Oxley

Matteo Cavaleri, Daniele D'Angeli, Alfredo Donno

This paper introduces a new graph construction, the permutational power of a graph, whose adjacency matrix is obtained by the composition of a permutation matrix with the adjacency matrix of the graph. It is shown that this construction recovers the class... see more

Neil Hindman, Dona Strauss, Luca Q. Zamboni

Lina Li, Theodore Molla

Joseph Briggs, Minki Kim

Krystal Guo, Tony Huynh, Marco Macchia

We determine the exact value of the biclique covering number for all grid graphs.

Pu Gao, Catherine Greenhill

Csilla Bujtas, Zsolt Tuza

Corey Vorland

J. Propp and T. Roby isolated a phenomenon in which a statistic on a set has the same average value over any orbit as its global average, naming it homomesy. They proved that the cardinality statistic on order ideals of the product of two chains poset und... see more

Zoltán Füredi, Alexandr Kostochka, Ruth Luo

Claude Tardif, Xuding Zhu

Roger Yu, Mikio Kano, Hongliang Lu

Henri Mühle, Nathan Williams

Kevin Leckey, Nick Wormald

Svenja Hüning, Wilfried Imrich, Judith Kloas, Hannah Schreber, Thomas W. Tucker

Julien Courtiel, Karen Yeats, Noam Zeilberger

We present a surprisingly new connection between two well-studied combinatorial classes: rooted connected chord diagrams on one hand, and rooted bridgeless combinatorial maps on the other hand. We describe a bijection between these two classes, which natu... see more

Martin Doležal, Jan Hladký

Hladký, Hu, and Piguet [Tilings in graphons, preprint] introduced the notions of matching and fractional vertex covers in graphons. These are counterparts to the corresponding notions in finite graphs. Combinatorial optimization studies the structure... see more

Young-Tak Oh, Euiyong Park

Robert Brignall, Jakub Sliacan

Nika Salia, Casey Tompkins, Zhiyu Wang, Oscar Zamora

Fiachra Knox, Bojan Mohar

Andrii Arman, Sergei Tsaturian

Xing Shi Cai, Cecilia Holmgren

Jacek Bojarski, Andrzej Piotr Kisielewicz, Krzysztof Przeslawski

Sándor Bozóki, Péter Gál, István Marosi, William D. Weakley

Robert Shwartz

In this paper we introduce the elementary factorization of the standard OGS for the symmetric group, and show how it encodes the inversion and descent set statistics. Proofs follow from exchange laws for powers of Coxeter elements in the principal flag.

Bernhard Gittenberger, Isabella Larcher

Ricky Xiaofeng Chen

Bethany Austhof, Sean English

Yi Zhang, Yi Zhao, Mei Lu

Ira M. Gessel

Egge, Loehr, and Warrington proved a formula for the Schur function expansion of a symmetric function in terms of its expansion in fundamental quasi-symmetric functions. Their formula involves the coefficients of a modified inverse Kostka matrix. Recently... see more

Niranjan Balachandran, Eshita Mazumdar

Gal Cohensius, Urban Larsson, Reshef Meir, David Wahlstedt

Shuya Chiba, Michitaka Furuya, Kenta Ozeki, Masao Tsugaki, Tomoki Yamashita

Padraig Condon, Alberto Espuny Díaz, Daniela Kühn, Deryk Osthus, Jaehoon Kim

Chris Dowden, Mihyun Kang, Mirjana Mikalacki, Miloš Stojakovic

Tobias Müller, Matej Stehlík

Stiebitz determined the chromatic number of generalised Mycielski graphs using the topological method of Lovász, which invokes the Borsuk–Ulam theorem. Van Ngoc and Tuza used elementary combinatorial arguments to prove Stiebitz's theor... see more

Maria Axenovich, Ursula Schade, Carsten Thomassen, Torsten Ueckerdt