Opened 3 years ago

Closed 3 years ago

#17118 closed enhancement (fixed)

Added multiplier computation to affine morphism

Reported by: gjorgenson Owned by:
Priority: minor Milestone: sage-6.4
Component: algebraic geometry Keywords:
Cc: Merged in:
Authors: Grayson Jorgenson Reviewers: Ben Hutz
Report Upstream: N/A Work issues:
Branch: e83be23 (Commits) Commit: e83be23b16a2cc68be090f6067af132ca403fc92
Dependencies: Stopgaps:

Description

Implement function to compute multipliers for periodic points of affine morphisms.

Change History (12)

comment:1 Changed 3 years ago by gjorgenson

  • Branch set to u/gjorgenson/ticket/17118
  • Created changed from 10/08/14 16:46:55 to 10/08/14 16:46:55
  • Modified changed from 10/08/14 16:46:55 to 10/08/14 16:46:55

comment:2 Changed 3 years ago by gjorgenson

  • Commit set to d5856dcf887886622e0739b0cee3495f994f90d8
  • Status changed from new to needs_review

New commits:

d5856dcAdded function that computes the multipliers of periodic points of affine morhpisms

comment:3 Changed 3 years ago by gjorgenson

  • Status changed from needs_review to needs_work

comment:4 Changed 3 years ago by gjorgenson

  • Status changed from needs_work to needs_review

comment:5 Changed 3 years ago by bhutz

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

A few things here

  • The docs say: 'at the QQ-rational point', but it does not need to be a QQ point
  • I don't understand this example: It seems to me that period 0 is bad input. Perhaps as part of 'check' you should check that period > 0.
sage: P.<x> = AffineSpace(CC,1)
sage: H = End(P)
sage: f = H([x^2 + 1/2])
sage: f.multiplier(P([0.5 + 0.5*I]),0)
  • I think
    NotImplementedError("Must be an endomorphism of affine space")
    

should be TypeError?, since you can't iterate a non-endomorphism

  • You didn't quite get subschemes working fully, see the error on this example:
sage: P.<x,y> = AffineSpace(QQ,2)
sage: X=P.subscheme([x^2-y^2])
sage: H = End(X)
sage: f = H([x^2,y^2])
sage: f.multiplier(X([1,1]),1)

comment:6 Changed 3 years ago by git

  • Commit changed from d5856dcf887886622e0739b0cee3495f994f90d8 to e7a9d145a1adab1bf9ec6b287b4a07078c9500b9

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

a5af987Minor changes to multiplier function for both affine/projective morphisms.
886e95fMinor doctest change in multiplier for affine morphisms
2cc284aMerged ticket with newest beta.
e7a9d14Merge branch 'master' into ticket/17118

comment:7 Changed 3 years ago by gjorgenson

  • Status changed from needs_work to needs_review

comment:8 Changed 3 years ago by bhutz

  • Status changed from needs_review to needs_work

Almost there, just a couple minor things since the functionality seems fine.

  • the comment

#get the correct order for chain rule matrix multiplication does not need the 'get the correct order' as that is only an issue for projective

  • Since you're allowing subschemes, all the places that say

must be an endomorphism of xxx space just need to say 'must be an endomorphism'. I count 4 such places.

comment:9 Changed 3 years ago by git

  • Commit changed from e7a9d145a1adab1bf9ec6b287b4a07078c9500b9 to e83be23b16a2cc68be090f6067af132ca403fc92

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

e83be23Minor changes in comments/documentation for multiplier function

comment:10 Changed 3 years ago by gjorgenson

  • Status changed from needs_work to needs_review

comment:11 Changed 3 years ago by bhutz

  • Status changed from needs_review to positive_review

Looks good.

comment:12 Changed 3 years ago by vbraun

  • Branch changed from u/gjorgenson/ticket/17118 to e83be23b16a2cc68be090f6067af132ca403fc92
  • Resolution set to fixed
  • Status changed from positive_review to closed
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