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In order theory, partially ordered sets are only equipped with one relation which decides the entire structure/Hasse diagram of the set. In this paper, we have presented how partially ordered sets can be studied under simultaneous partially…

General Mathematics · Mathematics 2023-07-03 Omprakash Atale

We study the space requirements of a sorting algorithm where only items that at the end will be adjacent are kept together. This is equivalent to the following combinatorial problem: Consider a string of fixed length n that starts as a…

Probability · Mathematics 2007-05-23 Svante Janson

Graded posets frequently arise throughout combinatorics, where it is natural to try to count the number of elements of a fixed rank. These counting problems are often $\#\textbf{P}$-complete, so we consider approximation algorithms for…

Data Structures and Algorithms · Computer Science 2023-04-11 Prateek Bhakta , Ben Cousins , Matthew Fahrbach , Dana Randall

We consider a simple model of imprecise comparisons: there exists some $\delta>0$ such that when a subject is given two elements to compare, if the values of those elements (as perceived by the subject) differ by at least $\delta$, then the…

Data Structures and Algorithms · Computer Science 2015-01-14 Miklos Ajtai , Vitaly Feldman , Avinatan Hassidim , Jelani Nelson

Motivated by generating personalized recommendations using ordinal (or preference) data, we study the question of learning a mixture of MultiNomial Logit (MNL) model, a parameterized class of distributions over permutations, from partial…

Machine Learning · Statistics 2014-11-04 Sewoong Oh , Devavrat Shah

We revisit the well-known problem of sorting under partial information: sort a finite set given the outcomes of comparisons between some pairs of elements. The input is a partially ordered set P, and solving the problem amounts to…

Data Structures and Algorithms · Computer Science 2013-01-22 Jean Cardinal , Samuel Fiorini , Gwenaël Joret , Raphaël Jungers , J. Ian Munro

Partially ordered models of time occur naturally in applications where agents or processes cannot perfectly communicate with each other, and can be traced back to the seminal work of Lamport. In this paper we consider the problem of…

Computational Complexity · Computer Science 2023-05-26 Leif Eriksson , Victor Lagerkvist

A common problem in machine learning is to rank a set of n items based on pairwise comparisons. Here ranking refers to partitioning the items into sets of pre-specified sizes according to their scores, which includes identification of the…

Machine Learning · Computer Science 2018-01-08 Reinhard Heckel , Max Simchowitz , Kannan Ramchandran , Martin J. Wainwright

Ranking over sets arise when users choose between groups of items. For example, a group may be of those movies deemed $5$ stars to them, or a customized tour package. It turns out, to model this data type properly, we need to investigate…

Machine Learning · Computer Science 2014-08-04 Truyen Tran , Dinh Phung , Svetha Venkatesh

The elements of a finite nonempty partially ordered set are exposed at independent uniform times in $[0,1]$ to a selector who, at any given time, can see the structure of the induced partial order on the exposed elements. The selector's…

Optimization and Control · Mathematics 2010-10-07 Ragnar Freij , Johan Wästlund

A simple method to produce a random order type is to take the order type of a random point set. We conjecture that many probability distributions on order types defined in this way are heavily concentrated and therefore sample inefficiently…

Computational Geometry · Computer Science 2020-06-05 Olivier Devillers , Philippe Duchon , Marc Glisse , Xavier Goaoc

A sequence of reversals that takes a signed permutation to the identity is perfect if at no step a common interval is broken. Determining a parsimonious perfect sequence of reversals that sorts a signed permutation is NP-hard. Here we show…

Combinatorics · Mathematics 2009-05-18 Mathilde Bouvel , Cedric Chauve , Marni Mishna , Dominique Rossin

Sorting has a natural generalization where the input consists of: (1) a ground set $X$ of size $n$, (2) a partial oracle $O_P$ specifying some fixed partial order $P$ on $X$ and (3) a linear oracle $O_L$ specifying a linear order $L$ that…

Data Structures and Algorithms · Computer Science 2024-08-01 Ivor van der Hoog , Daniel Rutschmann

We consider the problem of upper bounding the number of circular transpositions needed to sort a permutation. It is well known that any permutation can be sorted using at most $n(n-1)/2$ adjacent transpositions. We show that, if we allow…

Discrete Mathematics · Computer Science 2014-02-21 Anke van Zuylen , James Bieron , Frans Schalekamp , Gexin Yu

Although many authors have considered how many ternary comparisons it takes to sort a multiset $S$ of size $n$, the best known upper and lower bounds still differ by a term linear in $n$. In this paper we restrict our attention to online…

Data Structures and Algorithms · Computer Science 2009-07-07 Travis Gagie , Yakov Nekrich

We analyze the quantum query complexity of sorting under partial information. In this problem, we are given a partially ordered set $P$ and are asked to identify a linear extension of $P$ using pairwise comparisons. For the standard sorting…

Computational Complexity · Computer Science 2019-02-19 Jean Cardinal , Gwenaël Joret , Jérémie Roland

The ability to learn from limited data, or few-shot learning, is a desirable and often critical requirement for NLP systems. While many existing methods do poorly at learning from a handful of examples, large pretrained language models have…

Computation and Language · Computer Science 2021-06-04 Sawan Kumar , Partha Talukdar

Sorting is one of the most fundamental algorithms in computer science. Recently, Learned Sorts, which use machine learning to improve sorting speed, have attracted attention. While existing studies show that Learned Sort is empirically…

Data Structures and Algorithms · Computer Science 2025-11-11 Atsuki Sato , Yusuke Matsui

An ordered set-partition (or preferential arrangement) of n labeled elements represents a single ``hierarchy''; these are enumerated by the ordered Bell numbers. In this note we determine the number of ``hierarchical orderings'' or…

Combinatorics · Mathematics 2014-09-17 N. J. A. Sloane , Thomas Wieder

We show that several versions of Floyd and Rivest's algorithm Select for finding the $k$th smallest of $n$ elements require at most $n+\min\{k,n-k\}+o(n)$ comparisons on average and with high probability. This rectifies the analysis of…

Data Structures and Algorithms · Computer Science 2007-05-23 Krzysztof C. Kiwiel