Algebras and modules
Model category presentations
Geometry on formal duals of algebras
For a ring, an associative algebra over is a ring equipped with a ring inclusion .
If the -algebra is equipped with a ring homomorphism the other way round,
then it is called an augmented algebra.
An augmentation of a bare ring itself, being an associative algebra over the ring of integers , is a ring homomorphism to the integers
Every group algebra is canonically augmented, the augmentation map being the operation that forms the sum of coefficients of the canonical basis elements.
Revised on June 19, 2013 20:16:34
by Urs Schreiber