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Partially ordered patterns (POPs) generalize the notion of classical patterns studied in the literature in the context of permutations, words, compositions and partitions. In this paper, we give a number of general, and specific enumerative…

Combinatorics · Mathematics 2022-04-20 Sergey Kitaev , Artem Pyatkin

In this paper we investigate undirected discrete graphical tree models when all the variables in the system are binary, where leaves represent the observable variables and where all the inner nodes are unobserved. A novel approach based on…

Statistics Theory · Mathematics 2012-03-06 Piotr Zwiernik , Jim Q. Smith

We establish a bijection from the set of all permutations (of a given length) that avoid a pattern $q$ and a context-sensitive language.

Combinatorics · Mathematics 2007-05-23 Murray Elder

We study the relationship between two notions of pattern avoidance for involutions in the symmetric group and their restriction to fixed-point-free involutions. The first is classical, while the second appears in the geometry of certain…

Combinatorics · Mathematics 2022-03-01 Jonathan J. Fang , Zachary Hamaker , Justin M. Troyka

We set up a new notion of local convergence for permutations and we prove a characterization in terms of proportions of \emph{consecutive} pattern occurrences. We also characterize random limiting objects for this new topology introducing a…

Probability · Mathematics 2020-03-20 Jacopo Borga

Design patterns are distilled from many real systems to catalog common programming practice. However, some object-oriented design patterns are distorted or overly complicated because of the lack of supporting programming language constructs…

Programming Languages · Computer Science 2019-06-03 Gerald Baumgartner , Konstantin Läufer , Vincent F. Russo

We consider uniform random permutations in proper substitution-closed classes and study their limiting behavior in the sense of permutons. The limit depends on the generating series of the simple permutations in the class. Under a mild…

This paper completes a project to enumerate permutations avoiding a triple T of 4-letter patterns, in the sense of classical pattern avoidance, for every T. There are 317 symmetry classes of such triples T and previous papers have…

Combinatorics · Mathematics 2017-11-23 David Callan , Toufik Mansour , Mark Shattuck

We present a new probabilistic proof of Otter's asymptotic formula for the number of unlabelled trees with a given number of vertices. We additionally prove a new approximation result, showing that the total variation distance between…

Combinatorics · Mathematics 2026-03-11 Benedikt Stufler

Models of bags of words typically assume topic mixing so that the words in a single bag come from a limited number of topics. We show here that many sets of bag of words exhibit a very different pattern of variation than the patterns that…

Information Retrieval · Computer Science 2012-02-20 Nebojsa Jojic , Alessandro Perina

In this paper we study the enumeration and the construction, according to the number of ones, of particular binary words avoiding a fixed pattern. The growth of such words can be described by particular jumping and marked succession rules.…

Formal Languages and Automata Theory · Computer Science 2011-08-19 Stefano Bilotta , Elisa Pergola , Renzo Pinzani

Linear model trees are regression trees that incorporate linear models in the leaf nodes. This preserves the intuitive interpretation of decision trees and at the same time enables them to better capture linear relationships, which is hard…

Machine Learning · Statistics 2024-07-10 Jakob Raymaekers , Peter J. Rousseeuw , Tim Verdonck , Ruicong Yao

Inspired by the definition of modified ascent sequences, we introduce a new class of integer sequences called revised ascent sequences. These sequences are defined as Cayley permutations where each entry is a leftmost occurrence if and only…

Combinatorics · Mathematics 2025-05-09 Robin D. P. Zhou

In this paper, we study pattern avoidance in weak ascent sequences, giving some results for patterns of length 3. This is an analogous study to one given by Duncan and Steingr\'imsson (2011) for ascent sequences. More precisely, we provide…

Combinatorics · Mathematics 2024-09-04 Beáta Bényi , Toufik Mansour , José L. Ramírez

We establish a novel bijective encoding that represents permutations as forests of decorated (or enriched) trees. This allows us to prove local convergence of uniform random permutations from substitution-closed classes satisfying a…

Probability · Mathematics 2020-07-01 Jacopo Borga , Mathilde Bouvel , Valentin Féray , Benedikt Stufler

A permutation $\pi$ contains a pattern $\sigma$ if and only if there is a subsequence in $\pi$ with its letters are in the same relative order as those in $\sigma$. Partially ordered patterns (POPs) provide a convenient way to denote…

Combinatorics · Mathematics 2021-01-29 Kai Ting Keshia Yap , David Wehlau , Imed Zaguia

Tutte founded the theory of enumeration of planar maps in a series of papers in the 1960s. Rooted non-separable planar maps are in bijection with West-2-stack-sortable permutations, beta(1,0)-trees introduced by Cori, Jacquard and Schaeffer…

Combinatorics · Mathematics 2012-12-20 Sergey Kitaev , Pavel Salimov , Christopher Severs , Henning Ulfarsson

There is a widespread and longstanding belief that machine learning models are biased towards the majority class when learning from imbalanced binary response data, leading them to neglect or ignore the minority class. Motivated by a recent…

Machine Learning · Statistics 2026-01-29 Nathan Phelps , Daniel J. Lizotte , Douglas G. Woolford

Random Forests and related tree-based methods are popular for supervised learning from table based data. Apart from their ease of parallelization, their classification performance is also superior. However, this performance, especially…

Machine Learning · Computer Science 2023-07-25 Tom Hanika , Johannes Hirth

We consider the biased random walk on a tree constructed from the set of finite self-avoiding walks on a lattice, and use it to construct probability measures on infinite self-avoiding walks. The limit measure (if it exists) obtained when…

Probability · Mathematics 2019-12-25 Vincent Beffara , Cong Bang Huynh