827 research outputs found
Group corings
We introduce group corings, and study functors between categories of
comodules over group corings, and the relationship to graded modules over
graded rings. Galois group corings are defined, and a Structure Theorem for the
-comodules over a Galois group coring is given. We study (graded) Morita
contexts associated to a group coring. Our theory is applied to group corings
associated to a comodule algebra over a Hopf group coalgebra.Comment: 38 page
Curved differential graded algebras and corings
A relationship between curved differential algebras and corings is
established and explored. In particular it is shown that the category of
semi-free curved differential graded algebras is equivalent to the category of
corings with surjective counits. Under this equivalence, comodules over a
coring correspond to integrable connections or quasi-cohesive curved modules,
while contramodules over a coring correspond to a specific class of curved
modules introduced and termed Z-divergences in here.Comment: 25 page
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