Abstract
Basing ourselves on the categorical notions of central extensions and commutators in the framework of semi-abelian categories relative to a Birkhoff subcategory, we study central extensions of Leibniz algebras with respect to the Birkhoff subcategory of Lie algebras, called \(\mathsf {Lie}\)-central extensions. We obtain a six-term exact homology sequence associated to a \(\mathsf {Lie}\)-central extension. This sequence, together with the relative commutators, allows us to characterize several classes of \(\mathsf {Lie}\)-central extensions, such as \(\mathsf {Lie}\)-trivial extensions, \(\mathsf {Lie}\)-stem extensions and \(\mathsf {Lie}\)-stem covers, and to introduce and characterize \(\mathsf {Lie}\)-unicentral, \(\mathsf {Lie}\)-capable, \(\mathsf {Lie}\)-solvable and \(\mathsf {Lie}\)-nilpotent Leibniz algebras.
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The authors wish to thank Prof. Teimuraz Pirashvili and anonymous referees for their suggestions and help in improving the presentation of this paper. Authors were supported by Ministerio de Economía y Competitividad (Spain) (European FEDER support included), Grant MTM2013-43687-P. E. Khmaladze was supported by Xunta de Galicia, Grant EM2013/016 (European FEDER support included) and by Shota Rustaveli National Science Foundation, Grant FR/189/5-113/14.
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Casas, J.M., Khmaladze, E. On \(\mathsf {Lie}\)-central extensions of Leibniz algebras. RACSAM 111, 39–56 (2017). https://doi.org/10.1007/s13398-016-0274-6
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DOI: https://doi.org/10.1007/s13398-016-0274-6
Keywords
- \(\mathsf {Lie}\)-central extension
- Relative commutator
- \(\mathsf {Lie}\)-unicentral
- \(\mathsf {Lie}\)-capable
- \(\mathsf {Lie}\)-solvable
- \(\mathsf {Lie}\)-nilpotent Leibniz algebra