Expected Number of Distinct Subsequences in Randomly Generated Binary Strings

When considering binary strings, it's natural to wonder how many distinct subsequences might exist in a given string. Given that there is an existing algorithm which provides a straightforward way to compute the number of distinct subsequences in a fixed string, we might next be interested in t...

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Main Authors: Yonah Biers-Ariel, Anant Godbole, Elizabeth Kelley
Format: Article
Language:English
Published: Discrete Mathematics & Theoretical Computer Science 2018-06-01
Series:Discrete Mathematics & Theoretical Computer Science
Subjects:
Online Access:https://dmtcs.episciences.org/3287/pdf
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author Yonah Biers-Ariel
Anant Godbole
Elizabeth Kelley
author_facet Yonah Biers-Ariel
Anant Godbole
Elizabeth Kelley
author_sort Yonah Biers-Ariel
collection DOAJ
description When considering binary strings, it's natural to wonder how many distinct subsequences might exist in a given string. Given that there is an existing algorithm which provides a straightforward way to compute the number of distinct subsequences in a fixed string, we might next be interested in the expected number of distinct subsequences in random strings. This expected value is already known for random binary strings where each letter in the string is, independently, equally likely to be a 1 or a 0. We generalize this result to random strings where the letter 1 appears independently with probability $\alpha \in [0,1]$. Also, we make some progress in the case of random strings from an arbitrary alphabet as well as when the string is generated by a two-state Markov chain.
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spelling doaj.art-b89ccac7bb244e5c916d4286bf814e6d2024-03-07T15:33:33ZengDiscrete Mathematics & Theoretical Computer ScienceDiscrete Mathematics & Theoretical Computer Science1365-80502018-06-01Vol. 19 no. 2, Permutation...Permutation Patterns10.23638/DMTCS-19-2-103287Expected Number of Distinct Subsequences in Randomly Generated Binary StringsYonah Biers-ArielAnant GodboleElizabeth KelleyWhen considering binary strings, it's natural to wonder how many distinct subsequences might exist in a given string. Given that there is an existing algorithm which provides a straightforward way to compute the number of distinct subsequences in a fixed string, we might next be interested in the expected number of distinct subsequences in random strings. This expected value is already known for random binary strings where each letter in the string is, independently, equally likely to be a 1 or a 0. We generalize this result to random strings where the letter 1 appears independently with probability $\alpha \in [0,1]$. Also, we make some progress in the case of random strings from an arbitrary alphabet as well as when the string is generated by a two-state Markov chain.https://dmtcs.episciences.org/3287/pdfmathematics - combinatorics05d40, 60c05
spellingShingle Yonah Biers-Ariel
Anant Godbole
Elizabeth Kelley
Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
Discrete Mathematics & Theoretical Computer Science
mathematics - combinatorics
05d40, 60c05
title Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
title_full Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
title_fullStr Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
title_full_unstemmed Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
title_short Expected Number of Distinct Subsequences in Randomly Generated Binary Strings
title_sort expected number of distinct subsequences in randomly generated binary strings
topic mathematics - combinatorics
05d40, 60c05
url https://dmtcs.episciences.org/3287/pdf
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