Opened 11 months ago
Closed 9 months ago
#29469 closed enhancement (fixed)
Have method is_unit of QuotientRingElement and PolynomialQuotientRingElement return True in more cases
Reported by: | soehms | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-9.2 |
Component: | commutative algebra | Keywords: | quotient ring, polynomial, is_unit, invert |
Cc: | Merged in: | ||
Authors: | Sebastian Oehms | Reviewers: | Travis Scrimshaw |
Report Upstream: | N/A | Work issues: | |
Branch: | 0beccc8 (Commits, GitHub, GitLab) | Commit: | 0beccc8a6aa2d4074241137f6d264a9d1d9f98bb |
Dependencies: | Stopgaps: |
Description
In the case of both classes there are examples where is_unit
raises a NotImplementedError
even though the answer True
could easily be given:
sage: P.<x,y> = QQ[] sage: Q = P.quo([1-x*y]) sage: Q.inject_variables() Defining xbar, ybar sage: ybar.is_unit() Traceback (most recent call last): ... NotImplementedError:
but:
sage: ~ybar xbar
or:
sage: Z16x.<x> = Integers(16)[] sage: S.<y> = Z16x.quotient(x^2 + x + 1) sage: S(3).is_unit() Traceback (most recent call last): ... NotImplementedError: The base ring (=Ring of integers modulo 16) is not a field
but:
sage: Z16x(3).is_unit() True
This will be improved here. Se also this sage-devel thread.
Change History (7)
comment:1 Changed 11 months ago by
- Branch set to u/soehms/is_unit_quotient_ring_elemnts_29469
comment:2 Changed 11 months ago by
- Commit set to 85afe0a2ba045263981814a4f913dd2ff82fd9ba
- Status changed from new to needs_review
comment:3 Changed 11 months ago by
- Commit changed from 85afe0a2ba045263981814a4f913dd2ff82fd9ba to 0beccc8a6aa2d4074241137f6d264a9d1d9f98bb
Branch pushed to git repo; I updated commit sha1. New commits:
0beccc8 | 29469: fix doctest in matrix0
|
comment:4 Changed 10 months ago by
- Milestone changed from sage-9.1 to sage-9.2
Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.
comment:5 Changed 10 months ago by
- Reviewers set to Travis Scrimshaw
- Status changed from needs_review to positive_review
LGTM.
comment:6 Changed 10 months ago by
Thanks!
comment:7 Changed 9 months ago by
- Branch changed from u/soehms/is_unit_quotient_ring_elemnts_29469 to 0beccc8a6aa2d4074241137f6d264a9d1d9f98bb
- Resolution set to fixed
- Status changed from positive_review to closed
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New commits:
29469: initial