A decomposition theorem for Lefschetz modules

Omid Amini; June Huh; Matt Larson

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arXiv · 2511.02026

A decomposition theorem for Lefschetz modules

Omid Amini·June Huh·Matt Larson

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Abstract

A Lefschetz module is a module over a graded algebra $A$ that satisfies analogues of Poincar\'{e} duality, the Hard Lefschetz property, and the Hodge--Riemann relations with respect to an open convex cone $\mathscr{K}$ in the degree one part of $A$. We analyze its decomposition into indecomposable modules over subrings of $A$ that are generated by elements in the closure of $\mathscr{K}$, establishing structural results that parallel the decomposition theorem for morphisms of complex projective varieties. We use our theorems to recover key statements in combinatorial Hodge theory and illuminate the Hodge-theoretic aspects of the decomposition theorem in algebraic geometry.

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Omid Amini, June Huh, Matt Larson. 2025-11-03. A decomposition theorem for Lefschetz modules. https://arxiv.org/abs/2511.02026

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