[GAP Forum] Diagonalize of symmetric matrix 248x248

Bill Allombert Bill.Allombert at math.u-bordeaux1.fr
Sun Jan 13 12:54:16 GMT 2013


On Sun, Jan 13, 2013 at 01:16:41PM +0100, Bill Allombert wrote:
> On Sun, Jan 13, 2013 at 11:39:59AM +0100, Marek Mitros wrote:
> > In general you are right. In this case I've got information from G. Nebe,
> > that matrix is diagonalizable over rationals. So orthogonal representation
> > of Th group would have rational entries.
> 
> With PARI/GP, I found that the eigenvalues are:
> [238 230 228 220 218 216 214 212 210 208 206 204 202 200 198 196 194 192 190 188 186 184 182 180
> 178 176 174 172 170 168 166 160 158 156 24]
> with multiplicities
> [1 3 2 6 2 4 7 3 6 3 5 5 5 5 2 5 3 9 3 3 2 2 3 2 1 2 3 4 2 1 1 1 1 1 140]

Bah, obviously this is garbage, I did not input the matrix correctly.
Is it possible to dowload the matrix without doing a big copy-paste ?

Cheers,
Bill.



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