The number of distinct adjacent pairs in geometrically distributed words

A sequence of geometric random variables of length $n$ is a sequence of $n$ independent and identically distributed geometric random variables ($\Gamma_1, \Gamma_2, \dots, \Gamma_n$) where $\mathbb{P}(\Gamma_j=i)=pq^{i-1}$ for $1~\leq~j~\leq~n$ with $p+q=1.$ We study the number of distinct adjacent...

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Main Authors: Margaret Archibald, Aubrey Blecher, Charlotte Brennan, Arnold Knopfmacher, Stephan Wagner, Mark Ward
Format: Article
Language:English
Published: Discrete Mathematics & Theoretical Computer Science 2021-01-01
Series:Discrete Mathematics & Theoretical Computer Science
Subjects:
Online Access:https://dmtcs.episciences.org/5686/pdf
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author Margaret Archibald
Aubrey Blecher
Charlotte Brennan
Arnold Knopfmacher
Stephan Wagner
Mark Ward
author_facet Margaret Archibald
Aubrey Blecher
Charlotte Brennan
Arnold Knopfmacher
Stephan Wagner
Mark Ward
author_sort Margaret Archibald
collection DOAJ
description A sequence of geometric random variables of length $n$ is a sequence of $n$ independent and identically distributed geometric random variables ($\Gamma_1, \Gamma_2, \dots, \Gamma_n$) where $\mathbb{P}(\Gamma_j=i)=pq^{i-1}$ for $1~\leq~j~\leq~n$ with $p+q=1.$ We study the number of distinct adjacent two letter patterns in such sequences. Initially we directly count the number of distinct pairs in words of short length. Because of the rapid growth of the number of word patterns we change our approach to this problem by obtaining an expression for the expected number of distinct pairs in words of length $n$. We also obtain the asymptotics for the expected number as $n \to \infty$.
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spelling doaj.art-13e2db8c67414eb38411f9abbcbf2c2f2024-03-07T15:43:24ZengDiscrete Mathematics & Theoretical Computer ScienceDiscrete Mathematics & Theoretical Computer Science1365-80502021-01-01vol. 22 no. 4Analysis of Algorithms10.23638/DMTCS-22-4-105686The number of distinct adjacent pairs in geometrically distributed wordsMargaret ArchibaldAubrey BlecherCharlotte BrennanArnold KnopfmacherStephan WagnerMark WardA sequence of geometric random variables of length $n$ is a sequence of $n$ independent and identically distributed geometric random variables ($\Gamma_1, \Gamma_2, \dots, \Gamma_n$) where $\mathbb{P}(\Gamma_j=i)=pq^{i-1}$ for $1~\leq~j~\leq~n$ with $p+q=1.$ We study the number of distinct adjacent two letter patterns in such sequences. Initially we directly count the number of distinct pairs in words of short length. Because of the rapid growth of the number of word patterns we change our approach to this problem by obtaining an expression for the expected number of distinct pairs in words of length $n$. We also obtain the asymptotics for the expected number as $n \to \infty$.https://dmtcs.episciences.org/5686/pdfmathematics - combinatorics05a15, 05a05
spellingShingle Margaret Archibald
Aubrey Blecher
Charlotte Brennan
Arnold Knopfmacher
Stephan Wagner
Mark Ward
The number of distinct adjacent pairs in geometrically distributed words
Discrete Mathematics & Theoretical Computer Science
mathematics - combinatorics
05a15, 05a05
title The number of distinct adjacent pairs in geometrically distributed words
title_full The number of distinct adjacent pairs in geometrically distributed words
title_fullStr The number of distinct adjacent pairs in geometrically distributed words
title_full_unstemmed The number of distinct adjacent pairs in geometrically distributed words
title_short The number of distinct adjacent pairs in geometrically distributed words
title_sort number of distinct adjacent pairs in geometrically distributed words
topic mathematics - combinatorics
05a15, 05a05
url https://dmtcs.episciences.org/5686/pdf
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