Abstract
We study exponentiability of homomorphisms in varieties of universal algebras close to classical ones. After describing an “almost folklore” general result, we present a purely algebraic proof of “étale implies exponentiable”, alternative to the topologically motivated proof given in one of our previous papers, in a different context. We prove that only isomorphisms are exponentiable homomorphisms in ideal determined varieties and extend this to ideal determined categories. Finally, we give a complete characterization of exponentiable homomorphisms of semimodules over semirings.
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Dedicated to the memory of Horst Herrlich.
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Clementino, M.M., Hofmann, D. & Janelidze, G. On Exponentiable Morphisms in Classical Algebra. Appl Categor Struct 24, 733–742 (2016). https://doi.org/10.1007/s10485-016-9458-7
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DOI: https://doi.org/10.1007/s10485-016-9458-7