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Jul 16 at 1:18 answer added Wang Chao timeline score: 0
Jun 8, 2023 at 15:18 history edited John Baez CC BY-SA 4.0
fixed spelling of "semsimple"
Feb 9, 2022 at 14:27 answer added Benjamin Steinberg timeline score: 7
Feb 9, 2022 at 14:18 comment added H. E. @Echo If you mean we take product for all $n$, then it is not semisimple since a semisimple ring must be artinian and noetherian, and the infinite product of non-zero rings is neither artinian nor noetherian.
Feb 9, 2022 at 14:13 comment added H. E. @ R. van Dobben de Bruyn A ring is semisimple if it is a semisimple module as a left (or equivalently right) A-module, and a semisimple algebra is just a $k$-algebra which is semisimple as a ring.
Feb 9, 2022 at 14:08 comment added user473423 If you take the product of all matrix algebras $\mathrm{Mat}_n(k)$. Would that be semisimple in your definition?
Feb 9, 2022 at 13:39 comment added R. van Dobben de Bruyn What definition of semisimple are you using? I know a few different ones, but it's possible that they're only equivalent when you already assume finite-dimensionality.
Feb 9, 2022 at 12:25 comment added H. E. $A^e$ is the tensor product algebra $A \otimes_k A^{op}$ of $A$ and the opposite algebra $A^{op}$.
Feb 9, 2022 at 12:21 history edited H. E. CC BY-SA 4.0
added 36 characters in body
Feb 9, 2022 at 11:12 comment added user473423 What is the enveloping algebra? I only know this term in the context of Lie algebras.
S Feb 9, 2022 at 2:35 review First questions
Feb 9, 2022 at 2:37
S Feb 9, 2022 at 2:35 history asked H. E. CC BY-SA 4.0