Modules and comodules for corings
Fundamentalʹnaâ i prikladnaâ matematika, Tome 11 (2005) no. 2, pp. 51-72
A coring $C$ over a ring $A$ is an $(A,A)$-bimodule with a comultiplication $\Delta\colon C\to C\otimes_AC$ and a counit $\varepsilon\colon C\to A$, both being left and right $A$-linear mappings satisfying additional conditions. The dual spaces $C^*=\mathrm{Hom}_A(C,A)$ and ${}^*C={}_A\mathrm{Hom}(C,A)$ allow the ring structure and the right (left) comodules over $C$ can be considered as left (right) modules over ${}^*C$ (respectively, $C^*$). In fact, under weak restrictions on the $A$-module properties of $C$, the category of right $C$-comodules can be identified with the subcategory $\sigma[{}_{^*C}C]$ of ${}^*C$-Mod, i.e., the category subgenerated by the left ${}^*C$-module $C$. This point of view allows one to apply results from module theory to the investigation of coalgebras and comodules.
@article{FPM_2005_11_2_a3,
author = {R. Wisbauer},
title = {Modules and comodules for corings},
journal = {Fundamentalʹna\^a i prikladna\^a matematika},
pages = {51--72},
year = {2005},
volume = {11},
number = {2},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/FPM_2005_11_2_a3/}
}
R. Wisbauer. Modules and comodules for corings. Fundamentalʹnaâ i prikladnaâ matematika, Tome 11 (2005) no. 2, pp. 51-72. http://geodesic.mathdoc.fr/item/FPM_2005_11_2_a3/
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