A polynomial ring contains its basering #23203

saraedum · 2017-06-09T22:37:54Z

Currently, this fails

sage: R.<x> = ZZ[]
sage: S.<y> = R[]
sage: R.is_subring(S)
NotImplementedError

Depends on #23204

CC: @jpflori

Component: commutative algebra

Keywords: sd86.5, sd87

Author: Julian Rüth

Branch/Commit: 5f99cf9

Reviewer: Claire Tomesch

Issue created by migration from https://trac.sagemath.org/ticket/23203

The text was updated successfully, but these errors were encountered:

saraedum · 2017-06-09T23:19:02Z

Dependencies: #23204

saraedum · 2017-06-09T23:26:20Z

Branch: u/saraedum/a_polynomial_ring_contains_its_basering

saraedum · 2017-06-09T23:26:40Z

New commits:

`17b8374`	`A polynomial ring contains its basering`

saraedum · 2017-06-09T23:26:40Z

Commit: 17b8374

saraedum · 2017-06-09T23:27:01Z

comment:5

(needs review: the is_subring does not work without #23204.)

saraedum · 2017-06-10T01:12:27Z

Author: Julian Rüth

tscrim · 2017-06-23T00:06:42Z

comment:8

While it is a degenerate case, a polynomial ring could be isomorphic to its base ring:

sage: PolynomialRing(ZZ, [])
Multivariate Polynomial Ring in no variables over Integer Ring

roed314 · 2017-07-17T17:44:48Z

Changed keywords from sd86.5 to sd86.5, sd87

sagetrac-git · 2017-07-17T21:18:45Z

Changed commit from 17b8374 to a9d8b4f

sagetrac-git · 2017-07-17T21:18:45Z

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

`4b17dd8`	`Fixing doctest errors from the change to natural_map in ring homsets`
`80cd0ff`	`Merge branch 'develop' into t/23204/remove_ringhomomorphism_coercion`
`5c7d1b9`	`Merge branch 'develop' of git://trac.sagemath.org/sage into t/23204/remove_ringhomomorphism_coercion`
`2043ff3`	`Fixing doctest errors`
`d7eb179`	`Remove RingHomomorphism_coercion`
`dbd5b0d`	`fix morphism printing in doctests`
`f606020`	`Fixed some doctests`
`db5cee6`	`implement zero() for ring homsets`
`a42ebcf`	implement `__nonzero__` when there is no zero element
`a9d8b4f`	`Merge branch 't/23204/remove_ringhomomorphism_coercion' into t/23203/a_polynomial_ring_contains_its_basering`

sagetrac-git · 2017-07-20T18:12:57Z

Changed commit from a9d8b4f to 5f99cf9

sagetrac-git · 2017-07-20T18:12:57Z

Branch pushed to git repo; I updated commit sha1. New commits:

`5f99cf9`	`Merge branch 'develop' into t/23203/a_polynomial_ring_contains_its_basering`

sagetrac-cmt · 2017-07-20T20:34:47Z

Reviewer: cmt

jpflori · 2017-07-20T20:52:44Z

comment:13

Full names in reviewer field please :)

sagetrac-cmt · 2017-07-20T20:53:59Z

Changed reviewer from cmt to none

saraedum · 2017-07-21T01:11:25Z

Reviewer: Claire Tomesch

sagetrac-cmt · 2017-07-21T18:50:51Z

comment:16

After fetching and merging #23204 into my local branch for this ticket, I built sage. I then ran ./sage -coverage <files> for all the files listed in the diff for this ticket, and compared that to the results of running the same command for the latest build of develop (8.0 rc2). The same number of missing doctests occurred in each build for each file, and although the total number of doctests for src/sage/rings/morphism.pyx and src/sage/rings/polynomial/polynomial_element.pyx changed between the develop build and this build, this was to be expected given the number of methods deleted (__nonzero__ and is_zero) and the number of trivial methods added (is_injective and (is_surjective), respectively. So, it appears that functionally the doctest coverage remained the same.

I am still within the (lengthly) process of running ./sage -tp 8 --long src/ now. It has produced some errors, which I will attempt to replicate before posting about them. Running all of the doctests may have been a mistake... I will also retry a more limited set of doctests shortly as well.

adeines · 2017-07-21T18:58:26Z

comment:17

I just updated #23204 to fix typos in two of the doctest. If you are getting a two failures, you might try checking out the updated ticket.

Replying to @sagetrac-cmt:

After fetching and merging #23204 into my local branch for this ticket, I built sage. I then ran ./sage -coverage <files> for all the files listed in the diff for this ticket, and compared that to the results of running the same command for the latest build of develop (8.0 rc2). The same number of missing doctests occurred in each build for each file, and although the total number of doctests for src/sage/rings/morphism.pyx and src/sage/rings/polynomial/polynomial_element.pyx changed between the develop build and this build, this was to be expected given the number of methods deleted (__nonzero__ and is_zero) and the number of trivial methods added (is_injective and (is_surjective), respectively. So, it appears that functionally the doctest coverage remained the same.

I am still within the (lengthly) process of running ./sage -tp 8 --long src/ now. It has produced some errors, which I will attempt to replicate before posting about them. Running all of the doctests may have been a mistake... I will also retry a more limited set of doctests shortly as well.

sagetrac-cmt · 2017-07-21T21:56:57Z

comment:18

Okay, something in my configuration had gotten messed up, so I started over entirely. I just pulled the latest version of this branch (5f99cf980c), which has the content of #23204 already merged in, merged in the latest develop branch (74b03027bc), and rebuilt. I then ran the following limited set of doctests and got these results:

bash-3.2$ ./sage -tp 8 --long src/sage/structure/ src/sage/categories/ src/sage/rings/ src/sage/modular/ src/sage/schemes/

too few successful tests, not using stored timings
Running doctests with ID 2017-07-21-16-33-34-b8fb451a.
Git branch: t/23203/a_polynomial_ring_contains_its_basering
Using --optional=ccache,mpir,python2,sage
Sorting sources by runtime so that slower doctests are run first....
Doctesting 883 files using 8 threads.

...

sage -t --long src/sage/schemes/curves/projective_curve.py
**********************************************************************
File "src/sage/schemes/curves/projective_curve.py", line 1304, in sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model
Failed example:
    D = C.ordinary_model(); D # long time (2 seconds)
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model[8]>", line 1, in <module>
        D = C.ordinary_model(); D # long time (2 seconds)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/curves/projective_curve.py", line 1393, in ordinary_model
        emb = extension(C.singular_subscheme())
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/curves/projective_curve.py", line 1373, in extension
        pts = self.change_ring(F.embeddings(QQbar)[0]).rational_points()
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/generic/algebraic_scheme.py", line 1846, in change_ring
        I = [f.change_ring(R) for f in self.defining_polynomials()]
      File "sage/rings/polynomial/multi_polynomial.pyx", line 873, in sage.rings.polynomial.multi_polynomial.MPolynomial.change_ring (build/cythonized/sage/rings/polynomial/multi_polynomial.c:13133)
        return self.parent().change_ring(R)(self)
      File "sage/rings/polynomial/multi_polynomial_ring_generic.pyx", line 985, in sage.rings.polynomial.multi_polynomial_ring_generic.MPolynomialRing_generic.change_ring (build/cythonized/sage/rings/polynomial/multi_polynomial_ring_generic.c:15237)
        return PolynomialRing(base_ring, self.ngens(), names, order=order)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/rings/polynomial/polynomial_ring_constructor.py", line 438, in PolynomialRing
        raise TypeError('base_ring must be a ring')
    TypeError: base_ring must be a ring
**********************************************************************
File "src/sage/schemes/curves/projective_curve.py", line 1321, in sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model
Failed example:
    all([D.codomain().is_ordinary_singularity(Q) for Q in D.codomain().singular_points()]) # long time
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model[9]>", line 1, in <module>
        all([D.codomain().is_ordinary_singularity(Q) for Q in D.codomain().singular_points()]) # long time
    NameError: name 'D' is not defined
**********************************************************************
File "src/sage/schemes/curves/projective_curve.py", line 1329, in sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model
Failed example:
    C.ordinary_model() # long time (5 seconds)
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model[13]>", line 1, in <module>
        C.ordinary_model() # long time (5 seconds)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/curves/projective_curve.py", line 1393, in ordinary_model
        emb = extension(C.singular_subscheme())
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/curves/projective_curve.py", line 1373, in extension
        pts = self.change_ring(F.embeddings(QQbar)[0]).rational_points()
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/schemes/generic/algebraic_scheme.py", line 1846, in change_ring
        I = [f.change_ring(R) for f in self.defining_polynomials()]
      File "sage/rings/polynomial/multi_polynomial.pyx", line 873, in sage.rings.polynomial.multi_polynomial.MPolynomial.change_ring (build/cythonized/sage/rings/polynomial/multi_polynomial.c:13133)
        return self.parent().change_ring(R)(self)
      File "sage/rings/polynomial/multi_polynomial_ring_generic.pyx", line 985, in sage.rings.polynomial.multi_polynomial_ring_generic.MPolynomialRing_generic.change_ring (build/cythonized/sage/rings/polynomial/multi_polynomial_ring_generic.c:15237)
        return PolynomialRing(base_ring, self.ngens(), names, order=order)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/rings/polynomial/polynomial_ring_constructor.py", line 438, in PolynomialRing
        raise TypeError('base_ring must be a ring')
    TypeError: base_ring must be a ring
**********************************************************************
1 item had failures:
   3 of  15 in sage.schemes.curves.projective_curve.ProjectivePlaneCurve.ordinary_model
    [328 tests, 3 failures, 65.69 s]

...

----------------------------------------------------------------------
sage -t --long src/sage/schemes/curves/projective_curve.py  # 3 doctests failed
----------------------------------------------------------------------
Total time for all tests: 1958.8 seconds
    cpu time: 6272.7 seconds
    cumulative wall time: 15257.4 seconds

I also ran the same tests on the latest develop build (74b03027bc) and they passed, so it seems like there is still something to fix here.

Since I think someone with fresh eyes should take a look at this ticket the next time it comes up for review, I am taking my name out of the reviewer field.

sagetrac-cmt · 2017-07-21T22:05:51Z

Changed reviewer from Claire Tomesch to none

saraedum · 2017-07-21T22:31:35Z

comment:20

cmt: Thanks for pointing this out. This is a problem in #23204. I'll fix it there.

saraedum · 2017-07-21T22:42:08Z

comment:21

Fixed in #23204.

saraedum · 2017-07-22T02:17:20Z

Reviewer: Claire Tomesch

saraedum · 2017-07-22T02:18:31Z

comment:23

Claire: We usually do not remove people from the Reviewers field, i.e., it is just a list of everybody that had a look at the ticket.

sagetrac-cmt · 2017-07-22T14:27:30Z

comment:24

Julian: Thanks, and my apologies! I didn't realize that was the convention.

sagetrac-cmt · 2017-07-22T16:20:38Z

comment:25

I just merged the latest version of #23204 (382e2d1807) into the latest version of this ticket (5f99cf980c), rebuilt, and reran the same limited set of tests (./sage -tp 8 --long src/sage/structure/ src/sage/categories/ src/sage/rings/ src/sage/modular/ src/sage/schemes/) which all passed!

I am now running all doctests.

sagetrac-cmt · 2017-07-22T18:17:28Z

comment:26

I just ran all tests in src/sage and produced only the following weird failed tests:

$ ./sage -tp 8 --long src/sage/
too few successful tests, not using stored timings
Running doctests with ID 2017-07-22-12-22-47-8f9951fd.
Git branch: t/23203/a_polynomial_ring_contains_its_basering
Using --optional=ccache,mpir,python2,sage
Sorting sources by runtime so that slower doctests are run first....
Doctesting 2969 files using 8 threads.

...

sage -t --long src/sage/tests/cmdline.py
**********************************************************************
File "src/sage/tests/cmdline.py", line 814, in sage.tests.cmdline.test_executable
Failed example:
    test_executable(["sage", "--rst2sws", input, output])
Expected:
    ('', '', 0)
Got:
    ('',
     'Traceback (most recent call last):\n  File "/Sage/sage/src/bin/sage-rst2sws", line 131, in <module>\n    from sagenb.notebook.notebook import Notebook\n  File "/Sage/sage/local/lib/python2.7/site-packages/sagenb/notebook/notebook.py", line 46, in <module>\n    from . import js           # javascript\n  File "/Sage/sage/local/lib/python2.7/site-packages/sagenb/notebook/js.py", line 34, in <module>\n    from .compress.JavaScriptCompressor import JavaScriptCompressor\nImportError: No module named JavaScriptCompressor\n',
     1)
**********************************************************************
File "src/sage/tests/cmdline.py", line 817, in sage.tests.cmdline.test_executable
Failed example:
    f = tarfile.open(output, 'r')
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.tests.cmdline.test_executable[242]>", line 1, in <module>
        f = tarfile.open(output, 'r')
      File "/Sage/sage/local/lib/python2.7/tarfile.py", line 1680, in open
        raise ReadError("file could not be opened successfully")
    ReadError: file could not be opened successfully
**********************************************************************
File "src/sage/tests/cmdline.py", line 818, in sage.tests.cmdline.test_executable
Failed example:
    print(f.extractfile('sage_worksheet/worksheet.html').read())
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.tests.cmdline.test_executable[243]>", line 1, in <module>
        print(f.extractfile('sage_worksheet/worksheet.html').read())
    AttributeError: 'file' object has no attribute 'extractfile'
**********************************************************************
File "src/sage/tests/cmdline.py", line 832, in sage.tests.cmdline.test_executable
Failed example:
    print(f.extractfile('sage_worksheet/worksheet.txt').read())
Exception raised:
    Traceback (most recent call last):
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Sage/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.tests.cmdline.test_executable[244]>", line 1, in <module>
        print(f.extractfile('sage_worksheet/worksheet.txt').read())
    AttributeError: 'file' object has no attribute 'extractfile'
**********************************************************************
1 item had failures:
   4 of 246 in sage.tests.cmdline.test_executable
    [245 tests, 4 failures, 155.43 s]
----------------------------------------------------------------------
sage -t --long src/sage/tests/cmdline.py  # 4 doctests failed
----------------------------------------------------------------------

However! When I run these same doctests on my latest build of the develop branch (74b03027bc), the exact same tests also fail.

Therefore, I'm going to positively review this ticket -- if others think this is a problem they are welcome to revert the status as they see fit.

vbraun · 2017-08-03T22:11:29Z

Changed branch from u/saraedum/a_polynomial_ring_contains_its_basering to 5f99cf9

saraedum added this to the sage-8.0 milestone Jun 9, 2017

saraedum added c: commutative algebra labels Jun 9, 2017

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sagetrac-cmt mannequin added s: needs work and removed s: needs review labels Jul 21, 2017

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sagetrac-cmt mannequin added s: positive review and removed s: needs review labels Jul 22, 2017

vbraun removed the s: positive review label Aug 3, 2017

vbraun closed this as completed in 5bdfb52 Aug 3, 2017

saraedum mentioned this issue Dec 22, 2018

A framework for discrete valuations in Sage #21869

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A polynomial ring contains its basering #23203

A polynomial ring contains its basering #23203

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