Opened 3 years ago
Closed 3 years ago
#20780 closed enhancement (fixed)
add level parameter to rational_preimages for projective points
Reported by:  bhutz  Owned by:  bhutz 

Priority:  minor  Milestone:  sage7.3 
Component:  algebraic geometry  Keywords:  
Cc:  Merged in:  
Authors:  Ben Hutz  Reviewers:  Grayson Jorgenson, Rebecca Lauren Miller 
Report Upstream:  N/A  Work issues:  
Branch:  6377a27 (Commits)  Commit:  6377a27d9be3cf3b46657d294da38f88ee73d65e 
Dependencies:  Stopgaps: 
Description
When working with preimage trees it is usefull to compute more than just the first preimages of a given point. The ticket is to add a parameter to rational_preimages() to specify how far back to find preimages. I.e. find all points Q with f^k(Q) =P
for specified k
.
Change History (6)
comment:1 Changed 3 years ago by
 Branch set to u/bhutz/t/20780
 Commit set to e7db093e5e6d70000c9806e1555cb09ce579e997
 Status changed from new to needs_review
comment:2 Changed 3 years ago by
 Reviewers set to Grayson Jorgenson
I think this looks good. The code makes sense and appears to work as intended. I just found some really minor things:
algebraic_scheme.py
 line 2780  change TypeError? message to all lowercase
 Old issues present before this ticket that maybe could be addressed here:
 line 2680 
`False`
to``False``
 line 2711  some spacing in ProjectiveSpace? calls and in lists of defining polynomials
projective_homset.py
 line 182  the sorted() function takes any iterable and returns a list, so it shouldn't be necessary to convert rat_points to a list first
projective_morphism.py
 line 3920 spacing around '>'
 lines 3790  3793, formatting issues:
``k``th
and`k`th
don't seem to render well, and perhaps`P`
and`Q`
should be replaced with``P``
,``Q``
.  some ProjectiveSpace? calls in examples of rational_preimages don't have any spacing in the arguments
comment:3 Changed 3 years ago by
 Commit changed from e7db093e5e6d70000c9806e1555cb09ce579e997 to 6377a27d9be3cf3b46657d294da38f88ee73d65e
Branch pushed to git repo; I updated commit sha1. New commits:
6377a27  20780: minor fixes

comment:4 Changed 3 years ago by
Okay, this looks fine to me now.
comment:5 Changed 3 years ago by
 Reviewers changed from Grayson Jorgenson to Grayson Jorgenson, Rebecca Lauren Miller
 Status changed from needs_review to positive_review
Looks good to me.
comment:6 Changed 3 years ago by
 Branch changed from u/bhutz/t/20780 to 6377a27d9be3cf3b46657d294da38f88ee73d65e
 Resolution set to fixed
 Status changed from positive_review to closed
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New commits:
20780: add level parameter to rational_preimages