A finite modular lattice not embeddable in the lattice of formations of finite groups

We give a negative answer to Kourovka Problem 13.51 by constructing a modular lattice with 184 elements that admits no injective map preserving binary meets and joins into the lattice of formations of finite groups. The counterexample is the dual of an explicit incidence lattice with 91 points and 91 lines. We prove a six-variable Desargues implication for formations by a finite argument using formation residuals and pullbacks of epimorphisms. The dual incidence lattice violates this implication. The obstruction includes the convention that the empty class is a formation and does not require preservation of the least or greatest element.

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Publication Details

Journal
Zenodo (CERN European Organization for Nuclear Research)
Published
2026-09-21
DOI
https://doi.org/10.5281/zenodo.22863018
Primary Topic
Finite Group Theory Research
Type
preprint
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preprint

A finite modular lattice not embeddable in the lattice of formations of finite groups

Achyuth Jayadevan
Zenodo (CERN European Organization for Nuclear Research)
Finite Group Theory Research
preprint

A finite modular lattice not embeddable in the lattice of formations of finite groups

Achyuth Jayadevan
preprint en

Abstract

We give a negative answer to Kourovka Problem 13.51 by constructing a modular lattice with 184 elements that admits no injective map preserving binary meets and joins into the lattice of formations of finite groups. The counterexample is the dual of an explicit incidence lattice with 91 points and 91 lines. We prove a six-variable Desargues implication for formations by a finite argument using formation residuals and pullbacks of epimorphisms. The dual incidence lattice violates this implication. The obstruction includes the convention that the empty class is a formation and does not require preservation of the least or greatest element.

Zenodo (CERN European Organization for Nuclear Research)
Manipal Academy of Higher Education (IN)
Finite Group Theory Research
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