Opened 5 years ago
Closed 5 years ago
#21104 closed enhancement (fixed)
indeterminacy locus for rational maps
Reported by:  mmanes  Owned by:  

Priority:  minor  Milestone:  sage7.4 
Component:  algebraic geometry  Keywords:  
Cc:  Merged in:  
Authors:  Michelle Manes  Reviewers:  Ben Hutz 
Report Upstream:  N/A  Work issues:  
Branch:  8680cc0 (Commits, GitHub, GitLab)  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 5 years ago by
 Branch set to u/mmanes/indeterminacy_locus_for_rational_maps
comment:2 Changed 5 years ago by
 Commit set to 61ce7d74be9f9d37b06c75e5a0ece3bf0fd0fee8
 Status changed from new to needs_review
comment:3 Changed 5 years ago by
 Status changed from needs_review to needs_work
I want to add functionality for indeterminacy_points when the indeterminacy locus is a zerodimensional subscheme.
comment:4 Changed 5 years ago by
 Commit changed from 61ce7d74be9f9d37b06c75e5a0ece3bf0fd0fee8 to 380203928b2b97379b6d692189b387697522cec0
Branch pushed to git repo; I updated commit sha1. New commits:
3802039  21104: added function for indeterminacy_points

comment:5 Changed 5 years ago by
 Status changed from needs_work to needs_review
New commits:
3802039  21104: added function for indeterminacy_points

comment:6 Changed 5 years ago by
 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^2z^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^2t^2*y^2,y^2z^2,x^2t^2*z^2]) f.indeterminacy_points()
%time set_verbose(None) P.<x,y,z>=ProjectiveSpace(Qp(3),2) H=End(P) f=H([x^27*y^2,y^2z^2,x^27*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 5 years ago by
 Commit changed from 380203928b2b97379b6d692189b387697522cec0 to 8680cc054aae2cc0517dc6a5d6b8b8e1fdb59911
Branch pushed to git repo; I updated commit sha1. New commits:
8680cc0  21104: improved documentation and minor improvement to code

comment:8 Changed 5 years ago by
 Status changed from needs_work to needs_review
comment:9 Changed 5 years ago by
 Milestone changed from sage7.3 to sage7.4
 Status changed from needs_review to positive_review
comment:10 Changed 5 years ago by
 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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New commits:
21104: define indeterminacy_locus function