Opened 9 years ago
Closed 8 years ago
#12143 closed defect (duplicate)
PariError when creating a relative number field
Reported by: | culler | Owned by: | davidloeffler |
---|---|---|---|
Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | number fields | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | Marco Streng | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
Please close as duplicate of #252
sage: t = QQ['t'].gen() sage: K.<a> = QQ.extension(t^6 - 1/4*t^3 - 1/64) sage: s = K['s'].gen() sage: g = s^4 + 2*a^2*s^2 + a^4 + a sage: L.<b> = K.extension(g)
fails with PariError?: inconsistent data (12)
The failure occurs in: rings.number_field.number_field_rel.pari_relative_polynomial().polisirreducible()
If, instead, one tries:
sage: L.<b> = K.extension(g, check=False)
it fails with PariError?: (5)
This time it fails in: pari_absolute_base_polynomial().rnfequation(self.pari_relative_polynomial(), 1)
Change History (7)
comment:1 follow-up: ↓ 2 Changed 9 years ago by
comment:2 in reply to: ↑ 1 ; follow-up: ↓ 3 Changed 9 years ago by
Replying to culler:
Unfortunately I don't see any way to work around it in my project.
I think the following works:
sage: PQ.<t> = QQ[] sage: f = t^6 - 1/4*t^3 - 1/64 sage: f = PQ(pari(f).polredabs()) sage: K.<a> = QQ.extension(f) sage: s = K['s'].gen() sage: g = s^4 + 2*a^2*s^2 + a^4 + a sage: L.<b> = K.extension(g) sage: L Number Field in b with defining polynomial s^4 + 2*a^2*s^2 + a^4 + a over its base field sage: K Number Field in a with defining polynomial t^6 - 2*t^3 - 1
I think this technique could be used to sort out #252. But there are many details to be got right.
comment:3 in reply to: ↑ 2 Changed 9 years ago by
Replying to fwclarke:
Thanks! That is very helpful. It is not the whole story, I'm afraid, since I am working in a tower of extensions and the call pari(f) seems to fail if f does not have rational coefficients. Still, it gets things off the ground and gives me a hint about where to look for the rest of the answer.
comment:4 Changed 8 years ago by
- Description modified (diff)
- Status changed from new to needs_review
comment:5 Changed 8 years ago by
- Status changed from needs_review to positive_review
comment:6 Changed 8 years ago by
- Milestone changed from sage-5.10 to sage-duplicate/invalid/wontfix
comment:7 Changed 8 years ago by
- Resolution set to duplicate
- Reviewers set to Marco Streng
- Status changed from positive_review to closed
I see now that this is just another example of NumberField? not working with polynomials that are not monic or not integral, which goes back 5 years to #252. So feel free to close the ticket. Unfortunately I don't see any way to work around it in my project. Too bad.