Structure of semisimple ring (Wedderburn-Artin) in Rings and Categories of Modules - Frank W. Anderson, Kent R. Fuller (auth.)
Please explain that:
- "Now $_RR$ is direct sum off these traces". It's OK!
- "so (see 7) there is a finite set...". I read unit 7 and can't found that.
- $T_i$ is simple left ideal of the ring $Tr_R(T_i)$
- "Thus by 13.5 ..."