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Terminology issue regarding modules and representations

  1. Nov 13, 2008 #1


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    1. The problem statement, all variables and given/known data
    Given a field F, FS4 is a group algebra... we have a representation X that maps FS4 to 3x3 matrices over (presumably) F. Let V denote the FS4 module corresponding to X..... do stuff. My question is, what the heck is V supposed to be?

    I assumed that V is F3, but that seemingly contradicts what the question wants me to do. So is V the free module of the representation of FS4 over itself (and then why bother having a representation)? I can't think of what else it could be

    The full question can be found at


    sheet 5, question 3

    EDIT: I was wrong... if V=F3 the question's conclusion is correct. For some reason I was associating the 4 in S4 with F instead, and thought it had characteristic 4... I noticed my error when I realized a) it has characteristic 0 b) 4 isn't the characteristic of a field. Good job by me wasting an hour working in a non-existent field
    Last edited: Nov 13, 2008
  2. jcsd
  3. Nov 14, 2008 #2


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    Well the representation gives us a homomorphism from S_4 into GL(F^3). The induced action of the algebra FS_4 on F^3 induces an FS_4-module structure on F^3. So yes, V=F^3.
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