Opened 3 years ago
Closed 3 years ago
#24886 closed enhancement (fixed)
Implement onepoint suspension and face split of polyhedron
Reported by:  jipilab  Owned by:  

Priority:  major  Milestone:  sage8.3 
Component:  geometry  Keywords:  days93, polytope, thursdaysbdx, IMAPolyGeom 
Cc:  vdelecroix, moritz, mkoeppe, chapoton  Merged in:  
Authors:  JeanPhilippe Labbé  Reviewers:  Frédéric Chapoton, Vincent Delecroix 
Report Upstream:  N/A  Work issues:  
Branch:  2d78b87 (Commits, GitHub, GitLab)  Commit:  2d78b8760d4e3ee5ffe1634bc763b3889818e314 
Dependencies:  Stopgaps: 
Description (last modified by )
The onepoint suspension of a vertex v
of a polyhedron P
of dimension d
is obtained by placing P
in a dimension d+1
vector space where the last coordinate is 0, then placing a vertex "over" v
and a vertex "below" v
in the last coordinate and taking the convex hull.
One can do a similar construction for faces of polyhedron by placing the two vertices relative to the center of the face. This way we get the face split of P
.
On the way, the center
function also got modified in the case when it is only a vertex so that it returns the vertex. This was necessary to make the onepoint suspension consistent.
Change History (13)
comment:1 Changed 3 years ago by
 Branch set to u/jipilab/24886
 Commit set to 2dacbe12bf10300d8113ea4c4f709bc742eeb2df
comment:2 Changed 3 years ago by
 Status changed from new to needs_review
comment:3 Changed 3 years ago by
 Commit changed from 2dacbe12bf10300d8113ea4c4f709bc742eeb2df to 02fa0d96b88f24a5c54e2c97f49ad70a29c432f4
Branch pushed to git repo; I updated commit sha1. New commits:
02fa0d9  Merge branch 'sage8.2.b7' into onepointsus

comment:4 Changed 3 years ago by
typo: the face splitting the face ``face``
comment:5 Changed 3 years ago by
You should check that you obtain the same answer using a proper vertex or a face of dimension 0
sage: C = polytopes.cube() sage: C.faces(0) # dimension 0 faces (<0>, <1>, <2>, <3>, <4>, <5>, <6>, <7>) sage: C.vertices() # proper vertices (A vertex at (1, 1, 1), A vertex at (1, 1, 1), ... A vertex at (1, 1, 1))
comment:6 Changed 3 years ago by
The documentation would also be nicer with:
 a proper definition of
bypiramid
 specification that the newly added vertices will be at height 1 and 1
comment:7 Changed 3 years ago by
 Keywords thursdaysbdx added
 Status changed from needs_review to needs_work
comment:8 Changed 3 years ago by
 Commit changed from 02fa0d96b88f24a5c54e2c97f49ad70a29c432f4 to eef860f63f2d6b16348ea71f08035240ad02d575
Branch pushed to git repo; I updated commit sha1. Last 10 new commits:
7f5e125  fixed typos in polyhedra_quickref.rst

bd6c356  LateX > LaTeX in polytope_tikz.rst

b1ce45b  Several other corrections

d526f70  renamed tutorial files

d7896f8  Merge branch 'develop' into 22572

597b802  Merge branch sage8.2.rc1 into 22572

eee533a  Corrections from review

b74ae85  Made tests pass

1c9a654  Merge branch thematic tutorial into onepointsus

eef860f  Applied review suggestions

comment:9 Changed 3 years ago by
 Keywords IMAPolyGeom added
 Status changed from needs_work to needs_review
Hi,
Thanks Vincent for your review. I made the suggested changes (along with merging the tutorial).
I realized while making a test that the method center
was changing the base ring when it was taken over a vertex, I fixed that small thing on the way too.
comment:10 Changed 3 years ago by
 Commit changed from eef860f63f2d6b16348ea71f08035240ad02d575 to 2d78b8760d4e3ee5ffe1634bc763b3889818e314
Branch pushed to git repo; I updated commit sha1. New commits:
2d78b87  whitespaces

comment:11 Changed 3 years ago by
 Description modified (diff)
 Summary changed from Implement one point suspension and face split of polyhedron to Implement onepoint suspension and face split of polyhedron
comment:12 Changed 3 years ago by
 Milestone changed from sage8.2 to sage8.3
 Reviewers set to Frédéric Chapoton, Vincent Delecroix
 Status changed from needs_review to positive_review
ok, let it be too
comment:13 Changed 3 years ago by
 Branch changed from u/jipilab/24886 to 2d78b8760d4e3ee5ffe1634bc763b3889818e314
 Resolution set to fixed
 Status changed from positive_review to closed
New commits:
first version of ops
Second version of ops
whitespaces