Abstract
Basing ourselves on Janelidze and Kelly’s general notion of central extension, we study universal central extensions in the context of semi-abelian categories. We consider a new fundamental condition on composition of central extensions and give examples of categories which do, or do not, satisfy this condition.
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José Manuel Casas’s research was supported by Ministerio de Ciencia e Innovación (grant number MTM2009-14464-C02-02, includes European FEDER support) and by Xunta de Galicia (grant number Incite09 207 215 PR).
Tim Van der Linden works as chargé de recherches for Fonds de la Recherche Scientifique–FNRS. His research was supported by Centro de Matemática da Universidade de Coimbra and by Fundação para a Ciência e a Tecnologia (grant number SFRH/BPD/38797/2007).
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Casas, J.M., Van der Linden, T. Universal Central Extensions in Semi-Abelian Categories. Appl Categor Struct 22, 253–268 (2014). https://doi.org/10.1007/s10485-013-9304-0
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DOI: https://doi.org/10.1007/s10485-013-9304-0