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Journal Articles Communications in Algebra Year : 2022

On congruence modular varieties and Gumm categories


Starting from a characterization of the so-called Shifting Lemma by a property of the fibers of the fibration ¶E of split epimorphisms in the category E, on the model of what happens for Mal’tsev categories, we shall investigate it in two directions: (1) a new one: in following the golden thread of the abelian split epimorphisms naturally provided by this characterization; (2) a more expected one: in measuring the distance between the consequences of the Shifting Lemma in the varietal context of congruence modular varieties and in the much more general categorical one. Along the way we shall emphasize a quite amazing phenomenon we called algebraic crystallography.

Dates and versions

hal-04353389 , version 1 (19-12-2023)



Dominique Bourn. On congruence modular varieties and Gumm categories. Communications in Algebra, 2022, 50 (6), pp.2377-2407. ⟨10.1080/00927872.2021.2006679⟩. ⟨hal-04353389⟩
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