Timeline for matrix congruence and smith normal form
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 26 at 22:09 | comment | added | darij grinberg | @hans: Thank you! Still only for positive-definite forms, as I feared, but good to have nevertheless. | |
| Nov 26 at 20:41 | comment | added | hans | @darijgrinberg doc.sagemath.org/html/en/reference/quadratic_forms/sage/… | |
| Nov 25 at 19:13 | comment | added | darij grinberg | @hans: Can Sage really check lattices for isometry? I don't see this option. | |
| Jan 27, 2021 at 15:21 | comment | added | en kuo | @TylerLawson, no worries. I have another question, I can only find the algorithm of sage (or Magma) which can compute the automorphism group of definite form. Is there a way that at least we can compute some X for a given K (when K is an indefinite form)? | |
| Jan 16, 2021 at 17:19 | comment | added | Tyler Lawson | My apologies, I obviously made a mistake in the calculation. | |
| Jan 16, 2021 at 12:24 | answer | added | hans | timeline score: 3 | |
| Jan 16, 2021 at 2:10 | comment | added | en kuo | @TylerLawson, but I have used the sage. It seams like they are isomorphic over Q. But I am not sure it is isomorphic over Z. Let me check the invariant of what you mentioned. | |
| Jan 15, 2021 at 18:34 | comment | added | Tyler Lawson | A back-of-the-envelope calculation seems to indicate these two forms have different 3-adic Hasse-Witt invariants, which would mean that they are not isomorphic over $\Bbb Q$. | |
| Jan 15, 2021 at 17:28 | comment | added | en kuo | But I found that "is_rationally_isometric" function only works for number field but not integers | |
| Jan 15, 2021 at 16:57 | comment | added | en kuo | @hans, I have checked this quadratic form. I think this is what I want. | |
| Jan 15, 2021 at 12:00 | comment | added | en kuo | @hans, thanks, I will check them. | |
| Jan 15, 2021 at 11:43 | comment | added | hans | You just want to check if two define lattices are properly isometric. Any modern computer algebra system can do this, e.g. Sage or Magma. | |
| Jan 15, 2021 at 11:03 | history | asked | en kuo | CC BY-SA 4.0 |