Opened 2 years ago

Closed 2 years ago

#21104 closed enhancement (fixed)

indeterminacy locus for rational maps

Reported by: mmanes Owned by:
Priority: minor Milestone: sage-7.4
Component: algebraic geometry Keywords:
Cc: Merged in:
Authors: Michelle Manes Reviewers: Ben Hutz
Report Upstream: N/A Work issues:
Branch: 8680cc0 (Commits) Commit: 8680cc054aae2cc0517dc6a5d6b8b8e1fdb59911
Dependencies: Stopgaps:

Description

Create function to compute the indeterminancy locus of a rational map on projective space.

Change History (10)

comment:1 Changed 2 years ago by mmanes

  • Branch set to u/mmanes/indeterminacy_locus_for_rational_maps

comment:2 Changed 2 years ago by mmanes

  • Authors set to Michelle Manes
  • Commit set to 61ce7d74be9f9d37b06c75e5a0ece3bf0fd0fee8
  • Status changed from new to needs_review

New commits:

61ce7d721104: define indeterminacy_locus function

comment:3 Changed 2 years ago by mmanes

  • Status changed from needs_review to needs_work

I want to add functionality for indeterminacy_points when the indeterminacy locus is a zero-dimensional subscheme.

comment:4 Changed 2 years ago by git

  • Commit changed from 61ce7d74be9f9d37b06c75e5a0ece3bf0fd0fee8 to 380203928b2b97379b6d692189b387697522cec0

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

380203921104: added function for indeterminacy_points

comment:5 Changed 2 years ago by mmanes

  • Status changed from needs_work to needs_review

New commits:

380203921104: added function for indeterminacy_points

comment:6 Changed 2 years ago by bhutz

  • Reviewers set to Ben Hutz
  • Status changed from needs_review to needs_work

Everything works find, just a couple minor things

  • need to wrap long doc lines
  • do not need the line

F = self.base_ring()

  • output of indet_pts: spelling of indet.
  • double quote F everywhere it occurs in docs
  • if not F.is_field() should be inside F is not None if branch
  • need doctest to test that F works

Here are some interesting examples I was trying. They all work, so add which ever you think

%time
set_verbose(None)
P.<x,y,z>=ProjectiveSpace(QQ,2)
H=End(P)
f=H([x^2+y^2,y^2-z^2,x^2+z^2])
f.indeterminacy_points(F=QuadraticField(-1))
%time
set_verbose(None)
K.<t>=FunctionField(QQ)
P.<x,y,z>=ProjectiveSpace(K,2)
H=End(P)
f=H([x^2-t^2*y^2,y^2-z^2,x^2-t^2*z^2])
f.indeterminacy_points()
%time
set_verbose(None)
P.<x,y,z>=ProjectiveSpace(Qp(3),2)
H=End(P)
f=H([x^2-7*y^2,y^2-z^2,x^2-7*z^2])
f.indeterminacy_points()
  • you should add a warning/note of some kind in the docs about the fact that these functions do not normalize the coordinates for examples such as
P.<x,y,z>=ProjectiveSpace(QQ,2)
H=End(P)
f=H([x*x^2,x*y^2,x*z^2])
f.indeterminacy_locus()

comment:7 Changed 2 years ago by git

  • Commit changed from 380203928b2b97379b6d692189b387697522cec0 to 8680cc054aae2cc0517dc6a5d6b8b8e1fdb59911

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

8680cc021104: improved documentation and minor improvement to code

comment:8 Changed 2 years ago by mmanes

  • Status changed from needs_work to needs_review

comment:9 Changed 2 years ago by bhutz

  • Milestone changed from sage-7.3 to sage-7.4
  • Status changed from needs_review to positive_review

comment:10 Changed 2 years ago by vbraun

  • Branch changed from u/mmanes/indeterminacy_locus_for_rational_maps to 8680cc054aae2cc0517dc6a5d6b8b8e1fdb59911
  • Resolution set to fixed
  • Status changed from positive_review to closed
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