Lie algebra deformations in characteristic 2

Sofiane Bouarroudj, Alexei Lebedev, Dimitry Leites, Irina Shchepochkina

Research output: Contribution to journalArticlepeer-review


Of four types of Kaplansky algebras, type-2 and type-4 algebras have previously unobserved ℤ/2-gradings: nonlinear in roots. A method assigning a simple Lie superalgebra to every ℤ/2-graded simple Lie algebra in characteristic 2 is illustrated by seven new series. Type-2 algebras and one of the two type-4 algebras are demystified as nontrivial deforms (the results of deformations) of the alternate Hamiltonian algebras. The type-1 Kaplansky algebra is recognized as the derived of the nonalternate version of the Hamiltonian Lie algebra, the one that preserves a tensorial 2-form. Deforms corresponding to nontrivial cohomology classes can be isomorphic to the initial algebra, e.g., we confirm Grishkov's implicit claim and explicitly describe the Jurman algebra as such a "semitrivial"deform of the derived of the alternate Hamiltonian Lie algebra. This paper helps to sharpen the formulation of a conjecture describing all simple finite-dimensional Lie algebras over any algebraically closed field of nonzero characteristic and supports a conjecture of Dzhumadildaev and Kostrikin stating that all simple finite-dimensional modular Lie algebras are either of "standard"type or deforms thereof. In characteristic 2, we give sufficient conditions for the known deformations to be semitrivial.

Original languageEnglish (US)
Pages (from-to)353-402
Number of pages50
JournalMathematical Research Letters
Issue number2
StatePublished - 2015


  • Characteristic 2
  • Deformation
  • Jurman algebra
  • Kaplansky algebra
  • Kostrikin-Shafarevich conjecture
  • Lie algebra

ASJC Scopus subject areas

  • General Mathematics


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