#25839 closed defect (fixed)

Raise Error if Univariate PR used to construct ProjectiveSpace

Reported by: gh-Loops7 Owned by:
Priority: trivial Milestone: sage-8.3
Component: dynamics Keywords:
Cc: bhutz Merged in:
Authors: Joseph Lupo Reviewers: Ben Hutz
Report Upstream: N/A Work issues:
Branch: dc640e0 (Commits) Commit: dc640e059b0a047ff6ba5fa5620e1bc5ce016ec7
Dependencies: Stopgaps:

Description (last modified by bhutz)

We can initialize a ProjectiveSpace? object as follows:

sage: R.<x,y> = QQ[]
sage: P = ProjectiveSpace(R)

However, we get a strange, unclear error when we try

sage: R.<x> = QQ[]
sage: P = ProjectiveSpace(R)

A univariate or multivariate single variable polynomial ring should both construct a projective space of dimension 0. The univariate case fails.

Change History (10)

comment:1 Changed 21 months ago by gh-Loops7

  • Description modified (diff)
  • Status changed from new to needs_review
  • Summary changed from Raise Error if Univariate PR given to ProjectiveSpace to Raise Error if Univariate PR used to construct ProjectiveSpace

comment:2 Changed 21 months ago by gh-Loops7

  • Status changed from needs_review to needs_work

comment:3 Changed 21 months ago by gh-Loops7

  • Branch set to u/gh-Loops7/25839_ps_init
  • Commit set to a1ec95954a360c77073e3c22ff1cf532223549b8
  • Status changed from needs_work to needs_review

comment:4 Changed 21 months ago by git

  • Commit changed from a1ec95954a360c77073e3c22ff1cf532223549b8 to 0c4dd18605d0111aa38e0458dd0998be07bab600

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

0c4dd1825839: clarified projective space init error

comment:5 Changed 21 months ago by bhutz

Actually, I think the fix here should be the univariate ring does construct a dim 0 projecive space (which is just a single point). For example, for single variable multivariate polynomial rings everything works just fine

P=ProjectiveSpace(QQ,0)
R=P.coordinate_ring()
ProjectiveSpace(R)

So I think the line

if is_MPolynomialRing(n) and R is None:

just to needs to be an or for is_Poly or is_MPoly

comment:6 Changed 21 months ago by git

  • Commit changed from 0c4dd18605d0111aa38e0458dd0998be07bab600 to c03b06ca6745c2fe333163a52c3955206473c986

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

c03b06c25398: handle dim 0 case

comment:7 Changed 21 months ago by git

  • Commit changed from c03b06ca6745c2fe333163a52c3955206473c986 to 8a6e5b0de9ff8a481a577818bbeefb2802e1406a

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

8a6e5b025839: change doc

comment:8 Changed 21 months ago by git

  • Commit changed from 8a6e5b0de9ff8a481a577818bbeefb2802e1406a to dc640e059b0a047ff6ba5fa5620e1bc5ce016ec7

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

dc640e025839: added parentheses

comment:9 Changed 21 months ago by bhutz

  • Authors set to Joseph Lupo
  • Description modified (diff)
  • Reviewers set to Ben Hutz
  • Status changed from needs_review to positive_review

comment:10 Changed 19 months ago by vbraun

  • Branch changed from u/gh-Loops7/25839_ps_init to dc640e059b0a047ff6ba5fa5620e1bc5ce016ec7
  • Resolution set to fixed
  • Status changed from positive_review to closed
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