Opened 18 months ago
Last modified 16 months ago
#27828 new defect
Iterated polynomial quotient ring construction
Reported by: | katestange | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | |
Component: | finite rings | Keywords: | quotient ring, polynomial ring, finite field, construction |
Cc: | katestange | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
In v7.3, the following nested polynomial ring construction returns NotImplementedError?:
q = 11 n = 4 F = GF(q) rings = [ [F, F(-1)] ] for i in range(1,n): lastring = rings[i-1] S.<x> = PolynomialRing(lastring[0], 'x'); zetaname = 'z' + str(i); # z0 = -1, z1 = i, etc. R = S.quotient( x^2 - lastring[1], zetaname ) # take square root of last generator rings.append( [R, R.gen()] )
Here, changing n=4 to n=3 or changing q=11 to q=13 (or anything 1 mod 4) works fine.
On the other hand, in Sage v8.3, this now works for q=11 but is now broken (NotImplementedError?) for q=13.
So, clearly in v8.3, something from v7.3 got broken, and something got fixed.
However, this code really ought to work for all n and prime q.
Change History (2)
comment:1 Changed 16 months ago by
comment:2 Changed 16 months ago by
- Milestone sage-8.8 deleted
As the Sage-8.8 release milestone is pending, we should delete the sage-8.8 milestone for tickets that are not actively being worked on or that still require significant work to move forward. If you feel that this ticket should be included in the next Sage release at the soonest please set its milestone to the next release milestone (sage-8.9).
As the Sage-8.8 release milestone is pending, we should delete the sage-8.8 milestone for tickets that are not actively being worked on or that still require significant work to move forward. If you feel that this ticket should be included in the next Sage release at the soonest please set its milestone to the next release milestone (sage-8.9).