Opened 3 years ago
Closed 3 years ago
#29469 closed enhancement (fixed)
Have method is_unit of QuotientRingElement and PolynomialQuotientRingElement return True in more cases
Reported by: | soehms | Owned by: | |
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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 3 years ago by
Branch: | → u/soehms/is_unit_quotient_ring_elemnts_29469 |
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comment:2 Changed 3 years ago by
Authors: | → Sebastian Oehms |
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Commit: | → 85afe0a2ba045263981814a4f913dd2ff82fd9ba |
Status: | new → needs_review |
comment:3 Changed 3 years ago by
Commit: | 85afe0a2ba045263981814a4f913dd2ff82fd9ba → 0beccc8a6aa2d4074241137f6d264a9d1d9f98bb |
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Branch pushed to git repo; I updated commit sha1. New commits:
0beccc8 | 29469: fix doctest in matrix0
|
comment:4 Changed 3 years ago by
Milestone: | sage-9.1 → sage-9.2 |
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Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.
comment:5 Changed 3 years ago by
Reviewers: | → Travis Scrimshaw |
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Status: | needs_review → positive_review |
LGTM.
comment:7 Changed 3 years ago by
Branch: | u/soehms/is_unit_quotient_ring_elemnts_29469 → 0beccc8a6aa2d4074241137f6d264a9d1d9f98bb |
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Resolution: | → fixed |
Status: | positive_review → closed |
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New commits:
29469: initial