Opened 2 years ago

Closed 2 years ago

#23484 closed enhancement (fixed)

Zmod(nm) → Zmod(n) is surjective but not injective

Reported by: saraedum Owned by:
Priority: trivial Milestone: sage-8.1
Component: commutative algebra Keywords: sd87, beginner
Cc: Merged in:
Authors: Julian Rüth Reviewers: David Ayotte
Report Upstream: N/A Work issues:
Branch: 04f2da0 (Commits) Commit: 04f2da04780dc29ca4a7d9a78fc528dbea1c5687
Dependencies: #23204 Stopgaps:

Description (last modified by mwest)


Change History (16)

comment:1 Changed 2 years ago by saraedum

  • Branch set to u/saraedum/zmod_nm____zmod_n__is_surjective_but_not_injective

comment:2 Changed 2 years ago by saraedum

  • Commit set to 04f2da04780dc29ca4a7d9a78fc528dbea1c5687
  • Keywords sd87 added

New commits:

​04f2da0Zmod(nm) → Zmod(n) is surjective but not injective

comment:3 Changed 2 years ago by saraedum

  • Status changed from new to needs_review

comment:4 Changed 2 years ago by saraedum

  • Keywords beginner added

comment:5 Changed 2 years ago by davidayotte

  • Reviewers set to David Ayotte

comment:6 Changed 2 years ago by davidayotte

I ran a doctest and I got this error : 

File "src/sage/rings/finite_rings/integer_mod.pyx", line 4172, in sage.rings.finite_rings.integer_mod.IntegerMod_to_IntegerMod.is_surjective
Failed example:
    Zmod(4).hom(Zmod(2)).is_surjective()
Exception raised:
    Traceback (most recent call last):
      File "/tmp/sage-patchbot-0/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 509, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/tmp/sage-patchbot-0/sage/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 872, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.rings.finite_rings.integer_mod.IntegerMod_to_IntegerMod.is_surjective[0]>", line 1, in <module>
        Zmod(Integer(4)).hom(Zmod(Integer(2))).is_surjective()
      File "sage/categories/map.pyx", line 1204, in sage.categories.map.Map.is_surjective (build/cythonized/sage/categories/map.c:9227)
        raise NotImplementedError(type(self))
    NotImplementedError: <type 'sage.rings.morphism.RingHomomorphism_coercion'>

I haven't figured it out yet, but I'm checking it.

comment:7 Changed 2 years ago by saraedum

  • Dependencies set to #23204

comment:8 Changed 2 years ago by saraedum

There was a dependency missing. Sorry for that. Now it should work.

comment:9 Changed 2 years ago by davidayotte

Ok, in that case, everything seems right.

comment:10 Changed 2 years ago by saraedum

If you are happy with the changes you can set it to positive_review.

comment:11 Changed 2 years ago by davidayotte

I prefer to wait until #23204 is review, just to prevent any possible bugs.

comment:12 Changed 2 years ago by mwest

  • Description modified (diff)
  • Status changed from needs_review to positive_review

comment:13 Changed 2 years ago by mwest

  • Description modified (diff)

comment:14 Changed 2 years ago by saraedum

  • Status changed from positive_review to needs_work
  • Work issues set to failing doctest

comment:15 Changed 2 years ago by saraedum

  • Status changed from needs_work to positive_review
  • Work issues failing doctest deleted

The tests that the patchbot reports as failing are failing on other tickets as well, so not related to this ticket.

comment:16 Changed 2 years ago by vbraun

  • Branch changed from u/saraedum/zmod_nm____zmod_n__is_surjective_but_not_injective to 04f2da04780dc29ca4a7d9a78fc528dbea1c5687
  • Resolution set to fixed
  • Status changed from positive_review to closed
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