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Related papers: A look at generalized perfect shuffles

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We analyze the mixing time of a popular shuffling machine known as the shelf shuffler. It is a modified version of a $2m$-handed riffle shuffle ($m=10$ in casinos) in which a deck of $n$ cards is split multinomially into $2m$ piles, the…

Probability · Mathematics 2024-10-24 Andrea Ottolini , Ray Chen

We prove a theorem that reduces bounding the mixing time of a card shuffle to verifying a condition that involves only triplets of cards. Then we use it to analyze a classic model of card shuffling. In 1988, Diaconis introduced the…

Probability · Mathematics 2024-11-12 Olena Blumberg , Ben Morris , Alto Senda

The Thorp shuffle is defined as follows. Cut the deck into two equal piles. Drop the first card from the left pile or the right pile according to the outcome of a fair coin flip; then drop from the other pile. Continue this way until both…

Probability · Mathematics 2007-05-23 Ben Morris

We consider a problem of shuffling a deck of cards with ordered labels. Namely we split the deck of N=k^tq cards (where t>=1 is maximal) into k equally sized stacks and then take the top card off of each stack and sort them by the order of…

Combinatorics · Mathematics 2010-03-24 Steve Butler , Ron Graham

The starting point of this work is an equality between two quantities $A$ and $B$ found in the literature, which involve the {\em doubling-modulo-an-odd-integer} map, i.e., $x\in {\mathbb N} \mapsto 2x \bmod{(2n+1)}$ for some positive…

Number Theory · Mathematics 2025-04-25 Jean-Paul Allouche , Manon Stipulanti , Jia-Yan Yao

This paper is about the following question: How many riffle shuffles mix a deck of card for games such as blackjack and bridge? An object that comes up in answering this question is the descent polynomial associated with pairs of decks,…

Probability · Mathematics 2007-05-23 Mark Conger , D. Viswanath

Consider the following experiment: a deck with $m$ copies of $n$ different card types is randomly shuffled, and a guesser attempts to guess the cards sequentially as they are drawn. Each time a guess is made, some amount of "feedback" is…

Probability · Mathematics 2023-06-22 Persi Diaconis , Ron Graham , Xiaoyu He , Sam Spiro

We study how many riffle shuffles are required to mix n cards if only certain features of the deck are of interest, e.g. suits disregarded or only the colors of interest. For these features, the number of shuffles drops from 3/2 log_2(n) to…

Probability · Mathematics 2020-03-05 Sami Assaf , Persi Diaconis , K. Soundararajan

The number of ``carries'' when $n$ random integers are added forms a Markov chain [23]. We show that this Markov chain has the same transition matrix as the descent process when a deck of $n$ cards is repeatedly riffle shuffled. This gives…

Combinatorics · Mathematics 2008-06-24 Persi Diaconis , Jason Fulman

In the top to random shuffle, the first a cards are removed from a deck of n cards 12 \cdots n and then inserted back into the deck. This action can be studied by treating the top to random shuffle as an element B_a, which we define…

Combinatorics · Mathematics 2016-12-20 Roger Tian

This paper considers the effect of riffle shuffling on decks of cards, allowing for some cards to be indistinguishable from other cards. The dual problem of dealing a game with hands, such as bridge or poker, is also considered. The…

Probability · Mathematics 2010-02-10 Mark Conger , Jason Howald

A permutation is said to be a square if it can be obtained by shuffling two order-isomorphic patterns. The definition is intended to be the natural counterpart to the ordinary shuffle of words and languages. In this paper, we tackle the…

Data Structures and Algorithms · Computer Science 2016-03-04 Samuele Giraudo , Stéphane Vialette

This work introduces a new class of symmetric matrix structures, called harmonic structures, which enable the generation of all possible directed transitions $(x_i, x_{i+1})$ over a set of $n$ symbols, without internal repetitions. Unlike…

Combinatorics · Mathematics 2025-06-23 Nicolás Agustín Martínez

A formal n-square is the set of positions in an square matrix of size n. A shuffle of a formal n-square consists of independent rotations of each row and of each column. A key result turns out to be valid at least for n <= 34 and n = 37:…

Combinatorics · Mathematics 2017-01-11 M. Van de Vel

Inspired by a common technique for shuffling a deck of cards on a table without riffling, we formalize the pile shuffle and investigate its capabilities as a sorting device. Our study is novel in that we consider pile shuffle in three…

Combinatorics · Mathematics 2025-06-03 Kyle B. Treleaven

Mechanical shufflers used in many casinos employ a card shuffling scheme called \emph{shelf shuffling}. In a single-shelf shuffling, cards arrive sequentially, and each incoming card is independently placed on the top or the bottom of a…

Probability · Mathematics 2026-02-10 Raghavendra Tripathi

We study a family of shuffling operators on the symmetric group $S_n$, which includes the top-to-random shuffle. The general shuffling scheme consists of removing one card at a time from the deck (according to some probability distribution)…

Combinatorics · Mathematics 2024-05-30 Darij Grinberg , Nadia Lafrenière

The game of memory is played with a deck of n pairs of cards. The cards in each pair are identical. The deck is shuffled and the cards laid face down. A move consists of flipping over first one card then another. The cards are removed from…

Probability · Mathematics 2012-08-27 Daniel J. Velleman , Gregory S. Warrington

In the cyclic-to-random shuffle, we are given n cards arranged in a circle. At step k, we exchange the k'th card along the circle with a uniformly chosen random card. The problem of determining the mixing time of the cyclic-to-random…

Probability · Mathematics 2007-05-23 Elchanan Mossel , Yuval Peres , Alistair Sinclair

How many shuffles are needed to mix up a deck of cards? This question may be answered in the language of a random walk on the symmetric group, $S_{52}$. This generalises neatly to the study of random walks on finite groups, themselves a…

Probability · Mathematics 2015-04-22 J. P. McCarthy