Centroid is not commutative?

[algeboy]

Genus2Sig(
    m: KMatrixSpace of 5 by 5 matrices and dimension 2 over GF(5)
)
Genus2Signature(
    t: Tensor of valence 3, U2 x U1 >-> U0 U2 : Full Vector space o...
)
In file "c:/Users/autot/CODE/TameGenus\src\Basics.m", line 110, column 28:
>>     s := TensorOverCentroid(t);
                              ^
Runtime error in 'TensorOverCentroid': Centroid is not a commutative ring.

---

To reproduce bug: Use BrahanaTest(5) on Brahana group 2.

[joshmaglione]

This should be turned off since we are not doing proper field extensions at the moment, but clearly there's a radical somewhere. I guess we need one more integer as part of the genus 2 signature: the dimension of the radical.

[joshmaglione]

To reproduce bug: Use BrahanaTest(5) on Brahana group 2.

By the way, I think this function is unique to you. I do not have such a command.

[joshmaglione]

I'll let you close the issue if your code runs without issue.

[algeboy]

This test is in Auto-Sandbox/tests/BrahanaTest.m. Easy to reproduce from there, I wont close it because its not fixed its low priority. Probably just needs a radical wrapping, which is an issue in TensorSpace I've got to deal with.

[joshmaglione]

> BrahanaTest(5);

i= 1 ====================================================================

1  FAILED  
BrahanaTest(
    p: 5
)
AutomorphismGroupByInvariants(
    G: GrpPC
)
PseudoIsometryGroup(
    T: Tensor of valence 3, U2 x U1 >-> U0 U2 : Full Vector space o...
)
ActionOnCenter(
    T: Tensor of valence 3, U2 x U1 >-> U0 U2 : Full Vector space o...
)
RefineLinePartition(
    line_partition: [ { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 
    1...,
    lines: [ KMatrixSpace of 5 by 5 matrices and dimension 2 over GF(5)...,
    LineSignature: function(m) ... end function,
    LineSigEquals: function(sigA, sigB) ... end function
)
Genus2Sig(
    m: KMatrixSpace of 5 by 5 matrices and dimension 2 over GF(5)
)
Genus2Signature(
    t: Tensor of valence 3, U2 x U1 >-> U0 U2 : Full Vector space o...
)
__GetGenus2Signature(
    t: Tensor of valence 3, U2 x U1 >-> U0 U2 : Full Vector space o...
)
In file "/home/josh/TameGenus/src/Signatures.m", line 54, column 20:
>>   pfaff_prod := {@ &*(P) : P in pfaff_orbits @};
                      ^
Runtime error in '&*': Illegal null set

i= 2 ====================================================================

2  took time  0.210  and gave order  26301838717440000000000000000

Test 2 seems fine now. Looks like Test 1 is producing an error. I'll fix that now.

[joshmaglione]

Tests 1 and 2 are good now.