Opened 4 years ago
Closed 4 years ago
#17118 closed enhancement (fixed)
Added multiplier computation to affine morphism
Reported by:  gjorgenson  Owned by:  

Priority:  minor  Milestone:  sage6.4 
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 4 years ago by
 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 4 years ago by
 Commit set to d5856dcf887886622e0739b0cee3495f994f90d8
 Status changed from new to needs_review
comment:3 Changed 4 years ago by
 Status changed from needs_review to needs_work
comment:4 Changed 4 years ago by
 Status changed from needs_work to needs_review
comment:5 Changed 4 years ago by
 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 aQQ
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 nonendomorphism
 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^2y^2]) sage: H = End(X) sage: f = H([x^2,y^2]) sage: f.multiplier(X([1,1]),1)
comment:6 Changed 4 years ago by
 Commit changed from d5856dcf887886622e0739b0cee3495f994f90d8 to e7a9d145a1adab1bf9ec6b287b4a07078c9500b9
comment:7 Changed 4 years ago by
 Status changed from needs_work to needs_review
comment:8 Changed 4 years ago by
 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 4 years ago by
 Commit changed from e7a9d145a1adab1bf9ec6b287b4a07078c9500b9 to e83be23b16a2cc68be090f6067af132ca403fc92
Branch pushed to git repo; I updated commit sha1. New commits:
e83be23  Minor changes in comments/documentation for multiplier function

comment:10 Changed 4 years ago by
 Status changed from needs_work to needs_review
comment:12 Changed 4 years ago by
 Branch changed from u/gjorgenson/ticket/17118 to e83be23b16a2cc68be090f6067af132ca403fc92
 Resolution set to fixed
 Status changed from positive_review to closed
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New commits:
Added function that computes the multipliers of periodic points of affine morhpisms