Welfarist Formulations for Diverse Similarity Search

Fuente: arXiv
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Hauptverfasser: Barman, Siddharth, Das, Nirjhar, Gupta, Shivam, Shiragur, Kirankumar
Format: Preprint
Veröffentlicht: 2026
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author Barman, Siddharth
Das, Nirjhar
Gupta, Shivam
Shiragur, Kirankumar
author_facet Barman, Siddharth
Das, Nirjhar
Gupta, Shivam
Shiragur, Kirankumar
contents Nearest Neighbor Search (NNS) is a fundamental problem in data structures with wide-ranging applications, such as web search, recommendation systems, and, more recently, retrieval-augmented generations (RAG). In such recent applications, in addition to the relevance (similarity) of the returned neighbors, diversity among the neighbors is a central requirement. In this paper, we develop principled welfare-based formulations in NNS for realizing diversity across attributes. Our formulations are based on welfare functions -- from mathematical economics -- that satisfy central diversity (fairness) and relevance (economic efficiency) axioms. With a particular focus on Nash social welfare, we note that our welfare-based formulations provide objective functions that adaptively balance relevance and diversity in a query-dependent manner. Notably, such a balance was not present in the prior constraint-based approach, which forced a fixed level of diversity and optimized for relevance. In addition, our formulation provides a parametric way to control the trade-off between relevance and diversity, providing practitioners with flexibility to tailor search results to task-specific requirements. We develop efficient nearest neighbor algorithms with provable guarantees for the welfare-based objectives. Notably, our algorithm can be applied on top of any standard ANN method (i.e., use standard ANN method as a subroutine) to efficiently find neighbors that approximately maximize our welfare-based objectives. Experimental results demonstrate that our approach is practical and substantially improves diversity while maintaining high relevance of the retrieved neighbors.
format Preprint
id arxiv_https___arxiv_org_abs_2602_08742
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Welfarist Formulations for Diverse Similarity Search
Barman, Siddharth
Das, Nirjhar
Gupta, Shivam
Shiragur, Kirankumar
Data Structures and Algorithms
Computational Geometry
Computer Science and Game Theory
Information Retrieval
Machine Learning
Nearest Neighbor Search (NNS) is a fundamental problem in data structures with wide-ranging applications, such as web search, recommendation systems, and, more recently, retrieval-augmented generations (RAG). In such recent applications, in addition to the relevance (similarity) of the returned neighbors, diversity among the neighbors is a central requirement. In this paper, we develop principled welfare-based formulations in NNS for realizing diversity across attributes. Our formulations are based on welfare functions -- from mathematical economics -- that satisfy central diversity (fairness) and relevance (economic efficiency) axioms. With a particular focus on Nash social welfare, we note that our welfare-based formulations provide objective functions that adaptively balance relevance and diversity in a query-dependent manner. Notably, such a balance was not present in the prior constraint-based approach, which forced a fixed level of diversity and optimized for relevance. In addition, our formulation provides a parametric way to control the trade-off between relevance and diversity, providing practitioners with flexibility to tailor search results to task-specific requirements. We develop efficient nearest neighbor algorithms with provable guarantees for the welfare-based objectives. Notably, our algorithm can be applied on top of any standard ANN method (i.e., use standard ANN method as a subroutine) to efficiently find neighbors that approximately maximize our welfare-based objectives. Experimental results demonstrate that our approach is practical and substantially improves diversity while maintaining high relevance of the retrieved neighbors.
title Welfarist Formulations for Diverse Similarity Search
topic Data Structures and Algorithms
Computational Geometry
Computer Science and Game Theory
Information Retrieval
Machine Learning
url https://arxiv.org/abs/2602.08742