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Mar 15, 2015 at 22:45 comment added user6818 @DavidSpeyer And for the same set of matrices there seems to exist multiple different block diagonalizations.
Mar 15, 2015 at 21:17 history edited user6818 CC BY-SA 3.0
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Mar 15, 2015 at 21:09 comment added user6818 @DavidSpeyer I checked with an example that the similarity transformation that diagonalzies the center does not give the most irreducible decomposition of the other elements of the group. How does one find that basis which will do that?
Mar 15, 2015 at 6:41 comment added Student May be one has to go to the center and do this repearedly on each block to get the full reduction.
Mar 15, 2015 at 5:06 comment added Student In a given example if I find a similarity transformation which diagonalizes the center then that applied on everyone else doesn't produce the same block-diagonal structure. In an irreducible representation decomposition all the matrices should have the same block structure.
Mar 14, 2015 at 20:23 comment added user6818 @DavidSpeyer I am working over complex numbers. So you say that I can just detect the centre of the group and diagonalize any one of them and this basis should simultaneously block-diagonalize the rest of the matrices? But finding the center is still a brute-force calculation - right?
Mar 14, 2015 at 0:07 comment added Steve Huntsman Some old but rather explicit physics notes of mine on doing this in the context of a simple lattice gauge theory are here: drive.google.com/file/d/0ByTBBePgIzD0a3ZGSWt3aFlJS00/…
Mar 13, 2015 at 23:49 comment added David E Speyer Wait, is this a group in characteristic zero? Then I would compute the center of this group algebra (linear algebra) and diagonalize the central elements (since they commute).
Mar 13, 2015 at 21:44 comment added user6818 @DavidSpeyer Thanks! Isn't my case simpler than what that other question asks for? I am saying - lets say you have $8$ $4\times 4$ matrices given to you explicitly. Then what would you do?
Mar 13, 2015 at 21:32 comment added David E Speyer See math.stackexchange.com/a/185001/448 . If someone reading this knows a better place to point people than my answers, please do so!
Mar 13, 2015 at 21:30 history edited user6818 CC BY-SA 3.0
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Mar 13, 2015 at 21:22 history asked user6818 CC BY-SA 3.0