Achieving Approximate Symmetry Is Exponentially Easier than Exact Symmetry

Fuente: arXiv
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Main Authors: Tahmasebi, Behrooz, Weber, Melanie
Format: Preprint
Published: 2025
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author Tahmasebi, Behrooz
Weber, Melanie
author_facet Tahmasebi, Behrooz
Weber, Melanie
contents Enforcing exact symmetry in machine learning models often yields significant gains in scientific applications, serving as a powerful inductive bias. However, recent work suggests that relying on approximate symmetry can offer greater flexibility and robustness. Despite promising empirical evidence, there has been little theoretical understanding, and in particular, a direct comparison between exact and approximate symmetry is missing from the literature. In this paper, we initiate this study by asking: What is the cost of enforcing exact versus approximate symmetry? To address this question, we introduce averaging complexity, a framework for quantifying the cost of enforcing symmetry via averaging. Our main result is an exponential separation: under standard conditions, exact symmetry requires linear averaging complexity, whereas approximate symmetry can be attained with only logarithmic complexity in the group size. To the best of our knowledge, this provides the first theoretical separation of these two cases, formally justifying why approximate symmetry may be preferable in practice. Beyond this, our tools and techniques may be of independent interest for the broader study of symmetries in machine learning.
format Preprint
id arxiv_https___arxiv_org_abs_2512_11855
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Achieving Approximate Symmetry Is Exponentially Easier than Exact Symmetry
Tahmasebi, Behrooz
Weber, Melanie
Machine Learning
Artificial Intelligence
Enforcing exact symmetry in machine learning models often yields significant gains in scientific applications, serving as a powerful inductive bias. However, recent work suggests that relying on approximate symmetry can offer greater flexibility and robustness. Despite promising empirical evidence, there has been little theoretical understanding, and in particular, a direct comparison between exact and approximate symmetry is missing from the literature. In this paper, we initiate this study by asking: What is the cost of enforcing exact versus approximate symmetry? To address this question, we introduce averaging complexity, a framework for quantifying the cost of enforcing symmetry via averaging. Our main result is an exponential separation: under standard conditions, exact symmetry requires linear averaging complexity, whereas approximate symmetry can be attained with only logarithmic complexity in the group size. To the best of our knowledge, this provides the first theoretical separation of these two cases, formally justifying why approximate symmetry may be preferable in practice. Beyond this, our tools and techniques may be of independent interest for the broader study of symmetries in machine learning.
title Achieving Approximate Symmetry Is Exponentially Easier than Exact Symmetry
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2512.11855