Extensions of finite irreducible modules over rank two Lie conformal algebra
Lipeng Luo, Yucai Su, Mengjun Wang
TL;DR
This work delivers a complete classification of extensions of finite irreducible conformal modules over rank-two Lie conformal algebras, covering semisimple, solvable, and the two non-semisimple non-solvable types (Type I and Type II). The authors reduce the extension problem to solving cocycle equations, yielding explicit polynomial cocycles that describe nontrivial extensions between modules such as $V_{\\delta,\\alpha,\\beta}$, $V_{\\phi_A,\\phi_B}$, and $V_{\\alpha,\\beta}$ across the four algebra families. The results reveal a spectrum of extension dimensions, including 0, 1, 2, and, in many solvable cases, infinite-dimensional Ext spaces, with precise conditions under which each occurs and complete formulas for the cocycles. The findings advance the understanding of indecomposable finite conformal modules and provide a comprehensive foundation for further study in conformal representation theory and related algebraic structures.
Abstract
In this paper, we give a complete classification of extensions of finite irreducible conformal modules over rank two Lie conformal algebras.
