Haar-Type Measures on Topological Quasigroups and Kunen's Theorem
Abstract
Haar measure is a fundamental structure in harmonic analysis on locally compact groups. Its existence reflects the compatibility between topology and the associative algebraic structure of groups. In this paper we propose a framework for Haar-type measures on topological quasigroups. Since associativity is absent, strict translation invariance is generally too strong to expect. We therefore introduce quasi-invariant measures whose defect is measured by a modular cocycle attached to translations. We then explain, in a detailed and cautious form, how Moufang-type identities may impose strong constraints on this cocycle. In particular, under additional quasi-invariance assumptions for right translations, the Moufang-type identity leads naturally to a multiplicativity relation for the cocycle. This suggests a measure-theoretic interpretation of Kunen's theorem: the emergence of loop structure may be viewed as the collapse of a modular defect in the translation geometry of a quasigroup.
Cite
@article{arxiv.2603.06174,
title = {Haar-Type Measures on Topological Quasigroups and Kunen's Theorem},
author = {Takao Inoué},
journal= {arXiv preprint arXiv:2603.06174},
year = {2026}
}
Comments
25 pages. Minor revisions. Added a conceptual conjecture (Modular Collapse Conjecture), improved appendix diagrams, and clarified the interpretation of Kunen's theorem