# Homotopic Hopf-Galois extensions: foundations and examples

@article{Hess2009HomotopicHE, title={Homotopic Hopf-Galois extensions: foundations and examples}, author={Kathryn Hess}, journal={Geometry and Topology Monographs}, year={2009}, volume={16}, pages={79-132} }

Hopf‐Galois extensions of rings generalize Galois extensions, with the coaction of a Hopf algebra replacing the action of a group. Galois extensions with respect to a group G are the Hopf‐Galois extensions with respect to the dual of the group algebra of G . Rognes recently defined an analogous notion of Hopf‐Galois extensions in the category of structured ring spectra, motivated by the fundamental example of the unit map from the sphere spectrum to MU . This article introduces a theory of… Expand

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