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Simple Vectorial Lie Algebras in Characteristic 2 and their Superizations

Sofiane Bouarroudj, Pavel Grozman, Alexei Lebedev, Dimitry Leites, Irina Shchepochkina

Abstract

We overview the classifications of simple finite-dimensional modular Lie algebras. In characteristic 2, their list is wider than that in other characteristics; e.g., it contains desuperizations of modular analogs of complex simple vectorial Lie superalgebras. We consider odd parameters of deformations. For all 15 Weisfeiler gradings of the 5 exceptional families, and one Weisfeiler grading for each of 2 serial simple complex Lie superalgebras (with 2 exceptional subseries), we describe their characteristic-2 analogs - new simple Lie algebras. Descriptions of several of these analogs, and of their desuperizations, are far from obvious. One of the exceptional simple vectorial Lie algebras is a previously unknown deform (the result of a deformation) of the characteristic-2 version of the Lie algebra of divergence-free vector fields; this is a new simple Lie algebra with no analogs in characteristics distinct from 2. In characteristic 2, every simple Lie superalgebra can be obtained from a simple Lie algebra by one of the two methods described in arXiv:1407.1695. Most of the simple Lie superalgebras thus obtained from simple Lie algebras we describe here are new.

Simple Vectorial Lie Algebras in Characteristic 2 and their Superizations

Abstract

We overview the classifications of simple finite-dimensional modular Lie algebras. In characteristic 2, their list is wider than that in other characteristics; e.g., it contains desuperizations of modular analogs of complex simple vectorial Lie superalgebras. We consider odd parameters of deformations. For all 15 Weisfeiler gradings of the 5 exceptional families, and one Weisfeiler grading for each of 2 serial simple complex Lie superalgebras (with 2 exceptional subseries), we describe their characteristic-2 analogs - new simple Lie algebras. Descriptions of several of these analogs, and of their desuperizations, are far from obvious. One of the exceptional simple vectorial Lie algebras is a previously unknown deform (the result of a deformation) of the characteristic-2 version of the Lie algebra of divergence-free vector fields; this is a new simple Lie algebra with no analogs in characteristics distinct from 2. In characteristic 2, every simple Lie superalgebra can be obtained from a simple Lie algebra by one of the two methods described in arXiv:1407.1695. Most of the simple Lie superalgebras thus obtained from simple Lie algebras we describe here are new.

Paper Structure

This paper contains 53 sections, 3 theorems, 127 equations.

Key Result

Theorem 2.1

Brackets and squares of contact vector fields, and the corresponding contact brackets of generating functions, are given by formulas K_fbr. Both the contact brackets $\{-, -\}_{\rm k.b.}$ and $\{-, -\}_{\rm m.b.}$ are of the shape Then, for any $f, f_1, g, g_1\in \widehat{{\mathcal{F}}}$, we deduce

Theorems & Definitions (8)

  • Conjecture 1.1
  • Theorem 2.1: on explicit squaring and contact brackets for $p=2$
  • Lemma 2.2: A helpful lemma
  • Claim 2.3: Grading operators in ${\mathfrak{k}}(2n_{\bar{0}}+1;\underline{N}|m)$ and ${\mathfrak{m}}(n;\underline{N}|n+1)$
  • Claim 2.4: brackets in ${\mathfrak{k}}(2k_{\bar{0}}+1;\underline{N}|2k_{\bar{1}}+1)$
  • Claim 2.5: the second divergence on ${\mathfrak{k}}(1|2)$
  • Remark 2.7
  • Proposition 2.8: two exceptional deforms of the Poisson algebra