Opened 8 months ago
Closed 6 months ago
#30420 closed defect (duplicate)
Wrong Coercion of Elements in Padic-Extension Fields
Reported by: | gh-n-vi | Owned by: | |
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Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | padics | Keywords: | coercion, precision |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Below are attempts to coerce elements from a field T (a padic eisenstein extension field) into a field D, where D is similar to T, except that its precision is higher.
Some of these attempts produced wrong results.
The 2 examples below vary in the initial precision of the fields. However in both cases, the precision of D is twice the precision of T.
Example 1:
sage: T.<a> = Qp(31, 3).extension(x^3 - 31) sage: D.<b> = Qp(31, 6).extension(x^3 - 31) # Trying to coerce different elements from T to D: sage: D(29 + O(a^9)) # works 29 + O(b^9) sage: D(29*a^27 + O(a^36)) # wrong result 29*b^27 + 18*b^33 + O(b^36) sage: D(29*a^-27 + 3*a^-24 + 16*a^-23 + 28*a^-22 + 11*a^-21 + 22*a^-20 + 25*a^-19 + O(a^-18)) # wrong result O(b^-18) sage: D(29*a^-27 + 3*a^-24 + 16*a^-23 + 28*a^-22 + 11*a^-21 + 22*a^-20 + 25*a^-19) # wrong result O(b^-18)
Example 2:
sage: T.<a> = Qp(31, 20).extension(x^3 - 31) sage: D.<b> = Qp(31, 40).extension(x^3 - 31) # Trying to coerce different elements from T to D: sage: D(29 + O(a^9)) # works 29 + O(b^9) sage: D(29*a^27 + O(a^36)) # works 29*b^27 + O(b^36) sage: D(29*a^-27 + 3*a^-24 + 16*a^-23 + 28*a^-22 + 11*a^-21 + 22*a^-20 + 25*a^-19 + O(a^-18)) # wrong result O(b^-18) sage: D(29*a^-27 + 3*a^-24 + 16*a^-23 + 28*a^-22 + 11*a^-21 + 22*a^-20 + 25*a^-19) # wrong result 29*b^27 + 3*b^30 + 16*b^31 + 28*b^32 + O(b^33)
Change History (3)
comment:1 Changed 8 months ago by
- Milestone changed from sage-9.2 to sage-duplicate/invalid/wontfix
- Status changed from new to needs_review
comment:2 Changed 7 months ago by
- Status changed from needs_review to positive_review
comment:3 Changed 6 months ago by
- Resolution set to duplicate
- Status changed from positive_review to closed
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When using the most updated version of sage (including #29925, #29926 which might be relevant), and implementing the yet-unreviewed ticket #29927, the only one of the above examples which remains problematic is:
But this results from the problem in _polynomial_list() which is described in #29932. Indeed: