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 is also equipped with a ring homomorphism the other way round,
\epsilon \colon A \to R
then it is called an augmented algebra.
The kernel of is called the corresponding augmentation ideal in .
Every group algebra is canonically augmented, the augmentation map being the operation that forms the sum of coefficients of the canonical basis elements.
Created on October 14, 2012 17:42:54
by Urs Schreiber