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thetensor-space / TameGenus

Algorithms for isomorphism testing of groups with small genus
MIT License
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Genus2Signature #2

Closed joshmaglione closed 7 years ago

joshmaglione commented 7 years ago

Genus2Signature is sometimes saying two non-isomorphic groups have the same signature. See below.

The issue is that I run through each polynomial individually. The fix is to run through the multiset as a whole. The ordering is a little more complicated, but should be based off of the highest powers.

G:=PCGroup(\[ 12, -3, 3, 3, 3, 3, 3, 3, 3, 3, 3, -3, 3, 1417249, 6377618, 4960238, 22676115, 7558719, 1574811, 21262504, 5906536, 787888, 918760, 4269029, 9926081, 474365, 39742170, 3327174, 3313578, 737142, 306990, 102378, 45559591, 5738707, 1912927, 1687435, 562519, 24259, 31471, 45349640, 8739272, 5038880, 1679660, 323732, 55472, 18548, 17912, 9447849, 7873221, 1837113, 1399725, 379137, 213909,13041, 27093 ]);

H:=PCGroup(\[ 12, -3, 3, 3, 3, 3, 3, 3, 3, 3, 3, -3, 3, 1417249, 6377618, 708710, 2835651, 1890015, 630027, 14176624, 9449476, 2756188, 262660, 8520557, 7091729, 474365, 158153, 157733, 9981474, 11594034, 1660206, 369726, 184518, 163614, 45559591, 5738707, 847627, 562519, 70915, 54799, 19840472, 10865036, 5747468, 971072, 481196, 55472, 71036, 23744, 9447849, 4986393, 612405, 466617, 213909, 13041, 7653, 6945 ]);

IsIsomorphicSG(G,H); // false
Genus2Signature(G) eq Genus2Signature(H); // true
joshmaglione commented 7 years ago

All Pfaffians are irreducible, so multiply them all together and sort my lex-least.

joshmaglione commented 7 years ago

Fixed.