
Recent Posts
Archives
 May 2020
 April 2020
 March 2020
 June 2018
 July 2016
 June 2016
 May 2016
 March 2015
 February 2015
 January 2015
 December 2014
 December 2013
 November 2013
 July 2013
 June 2013
 May 2013
 March 2013
 February 2013
 January 2013
 December 2012
 November 2012
 October 2012
 September 2012
 August 2012
 April 2012
 March 2012
 February 2012
 January 2012
 December 2011
 November 2011
 October 2011
Categories
Meta
Pages
Monthly Archives: January 2015
The Group Algebra (III)
As alluded to at the end of the previous article, we shall consider the case where K is algebraically closed, i.e. every polynomial with coefficients in K factors as a product of linear polynomials. E.g. K = C is a common choice. Having assumed … Continue reading
Posted in Notes
Tagged character theory, division rings, group algebras, quaternions, semisimple rings, simple modules
Leave a comment
The Group Algebra (II)
We continue our discussion of the group algebra. Constructing K[G]modules Recall that such a module V is also called a representation of G over K, and corresponds to a group homomorphism (i) Given a K[G]module V, a submodule W of V is precisely a vector subspace W such that g(W) ⊆ W for … Continue reading
Posted in Notes
Leave a comment
The Group Algebra (I)
[ Note: the contents of this article overlap with a previous series on character theory. ] Let K be a field and G a finite group. The group algebra K[G] is defined to be a vector space over K with basis , where “g” here is … Continue reading
Posted in Notes
Tagged character theory, group actions, group algebras, modules, representation theory, semisimple rings, simple modules
Leave a comment