Example of an algebra finite over a commutative subalgebra with infinite dimensional simple modules - MathOverflow most recent 30 from http://mathoverflow.net2013-06-19T01:18:51Zhttp://mathoverflow.net/feeds/question/28784http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/28784/example-of-an-algebra-finite-over-a-commutative-subalgebra-with-infinite-dimensioExample of an algebra finite over a commutative subalgebra with infinite dimensional simple modulesBedini2010-06-19T22:59:17Z2010-06-21T15:18:16Z
<p>Let $A$ be an algebra over an algebraically closed field $k.$ Recall that if $A$ is
a finitely generated module over its center, and if its center is a finitely generated
algebra over $k,$ then by the Schur's lemma all simple $A$-modules are finite dimensional
over $k.$ </p>
<p>Motivated by the above, I would like an example of a $k$-algebra $A,$ such that:</p>
<p>1) $A$
has a simple module of infinitie dimension over $k,$ </p>
<p>2) $A$ contains
a commutative finitely generated subalgebra over which $A$ is a finitely generated
left and right module. </p>
<p>Thanks in advance.</p>
http://mathoverflow.net/questions/28784/example-of-an-algebra-finite-over-a-commutative-subalgebra-with-infinite-dimensio/28816#28816Answer by Bugs Bunny for Example of an algebra finite over a commutative subalgebra with infinite dimensional simple modulesBugs Bunny2010-06-20T07:58:40Z2010-06-21T15:18:16Z<p>Doc, this is a stinker. Your condition (2) forces your algebra to be finitely generated PI, and every little hare knows that simple modules over such algebras are finite-dimensional. See 13.4.9 and 13.10.3 of McConnell-Robson...</p>