A Simple Approximation Algorithm for Optimal Decision Tree

Fuente: arXiv
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Autori principali: Zhuo, Zhengjia, Nagarajan, Viswanath
Natura: Preprint
Pubblicazione: 2025
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author Zhuo, Zhengjia
Nagarajan, Viswanath
author_facet Zhuo, Zhengjia
Nagarajan, Viswanath
contents Optimal decision tree (\odt) is a fundamental problem arising in applications such as active learning, entity identification, and medical diagnosis. An instance of \odt is given by $m$ hypotheses, out of which an unknown ``true'' hypothesis is drawn according to some probability distribution. An algorithm needs to identify the true hypothesis by making queries: each query incurs a cost and has a known response for each hypothesis. The goal is to minimize the expected query cost to identify the true hypothesis. We consider the most general setting with arbitrary costs, probabilities and responses. \odt is NP-hard to approximate better than $\ln m$ and there are $O(\ln m)$ approximation algorithms known for it. However, these algorithms and/or their analyses are quite complex. Moreover, the leading constant factors are large. We provide a simple algorithm and analysis for \odt, proving an approximation ratio of $8 \ln m$.
format Preprint
id arxiv_https___arxiv_org_abs_2505_15641
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Simple Approximation Algorithm for Optimal Decision Tree
Zhuo, Zhengjia
Nagarajan, Viswanath
Data Structures and Algorithms
Machine Learning
Optimal decision tree (\odt) is a fundamental problem arising in applications such as active learning, entity identification, and medical diagnosis. An instance of \odt is given by $m$ hypotheses, out of which an unknown ``true'' hypothesis is drawn according to some probability distribution. An algorithm needs to identify the true hypothesis by making queries: each query incurs a cost and has a known response for each hypothesis. The goal is to minimize the expected query cost to identify the true hypothesis. We consider the most general setting with arbitrary costs, probabilities and responses. \odt is NP-hard to approximate better than $\ln m$ and there are $O(\ln m)$ approximation algorithms known for it. However, these algorithms and/or their analyses are quite complex. Moreover, the leading constant factors are large. We provide a simple algorithm and analysis for \odt, proving an approximation ratio of $8 \ln m$.
title A Simple Approximation Algorithm for Optimal Decision Tree
topic Data Structures and Algorithms
Machine Learning
url https://arxiv.org/abs/2505.15641