Opened 6 years ago

Closed 6 years ago

Last modified 6 years ago

#17855 closed enhancement (fixed)

create is_preperiodic function for points of projective space

Reported by: bhutz Owned by: bhutz
Priority: minor Milestone: sage-6.7
Component: algebraic geometry Keywords:
Cc: Merged in:
Authors: Ben Hutz Reviewers: Grayson Jorgenson
Report Upstream: N/A Work issues:
Branch: 476cf36 (Commits, GitHub, GitLab) Commit:
Dependencies: Stopgaps:

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Description

The function will take a point and map as input and return a boolean of whether or not the point is preperiodic for the map. Perhaps there should be an option to also return the period if the point is preperiodic

Change History (12)

comment:1 Changed 6 years ago by bhutz

  • Branch set to u/bhutz/ticket/17855
  • Created changed from 02/25/15 17:32:59 to 02/25/15 17:32:59
  • Modified changed from 02/25/15 17:32:59 to 02/25/15 17:32:59

comment:2 Changed 6 years ago by git

  • Commit set to f2f641403f8e05e7345a2ffb132b6cfcb8695b9b

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

​f2f6414Merge branch 'master' into ticket/17855

comment:3 Changed 6 years ago by bhutz

  • Authors set to Ben Hutz
  • Status changed from new to needs_review

This incorporated a few additional changes

  • there was an error in the error_bound canonical height computations which is now corrected
  • heights and canonical heights are now computable for QQbar points
  • methods to change QQbar points and maps to number field points and maps
  • change_ring now accepts an embedding for points and maps

comment:4 Changed 6 years ago by gjorgenson

  • Status changed from needs_review to needs_work

These examples don't seem to work: 

P.<x,y,z> = ProjectiveSpace(QQbar,2)
H = Hom(P,P)
f = H([x^2,y^2,z^2])
Q = P([1,1,1])
Q.is_preperiodic(f)

P.<x,y,z> = ProjectiveSpace(QQbar,2)
H = Hom(P,P)
f = H([x^2,y^2,z^2])
Q = P([QQbar(I),1,0])
Q.is_preperiodic(f)

comment:5 Changed 6 years ago by git

  • Commit changed from f2f641403f8e05e7345a2ffb132b6cfcb8695b9b to 06f4c355c940be11eef57bccfbd474de7a8952f3

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

​06f4c3517855: fix issues from review

comment:6 Changed 6 years ago by bhutz

  • Status changed from needs_work to needs_review

Yes, there were a couple issues with getting the right compositum base field. These should be fixed now.

comment:7 Changed 6 years ago by gjorgenson

From the review, for is_preperiodic need:

  • check that map is a morphism
  • check that given point is in the domain of the map
  • check that if over a number field, it is an absolute number field

comment:8 Changed 6 years ago by git

  • Commit changed from 06f4c355c940be11eef57bccfbd474de7a8952f3 to 476cf364e6b2f8df396df10141b96763e5a38f16

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

​476cf3617855: fix additional input cases

comment:9 Changed 6 years ago by gjorgenson

  • Status changed from needs_review to positive_review

Everything seems to be working well and the changes fixed all of the issues from the reviews.

comment:10 Changed 6 years ago by gjorgenson

  • Reviewers set to Grayson Jorgenson

comment:11 Changed 6 years ago by vbraun

  • Branch changed from u/bhutz/ticket/17855 to 476cf364e6b2f8df396df10141b96763e5a38f16
  • Resolution set to fixed
  • Status changed from positive_review to closed

comment:12 Changed 6 years ago by bhutz

  • Commit 476cf364e6b2f8df396df10141b96763e5a38f16 deleted
  • Milestone changed from sage-6.6 to sage-6.7
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