Implement (sub)direct sums of polytopes

[jplab]

From ​https://www.csun.edu/~ctoth/Handbook/chap15.pdf:

The (d+d)-dimensional polytope P⊕Q:=conv({(p,0)∈R^(d+d')|p∈P}∪{(0,p')∈R^(d+d')|q∈Q}). Thus the subdirect sum P⊕Q is a projection of the join P∗Q. The join is implemented in #24848.

Depends on #24848
Depends on #22572

CC: @videlec @mo271 @mkoeppe @fchapoton

Component: geometry

Keywords: days93, polytope

Author: Jean-Philippe Labbé

Branch/Commit: ffe21e2

Reviewer: Frédéric Chapoton

Issue created by migration from https://trac.sagemath.org/ticket/24849

[jplab]

Branch: u/jipilab/24849

[jplab]

New commits:

6eb0825

first version of (sub)direct sum

[jplab]

Dependencies: #24848, #22572

[jplab]

Commit: 6eb0825

[sagetrac-git]

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

b063975

typo

[sagetrac-git]

Changed commit from 6eb0825 to b063975

[sagetrac-git]

Changed commit from b063975 to d0242f3

[sagetrac-git]

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

d0242f3

removed translation from direct sum

[sagetrac-git]

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

0295def

whitespaces

[sagetrac-git]

Changed commit from d0242f3 to 0295def

[sagetrac-git]

Changed commit from 0295def to 2457e97

[sagetrac-git]

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

2457e97

Conventions in docstring

[sagetrac-git]

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

c807893	first version of the join
a14d2c7	pep8
347f99f	Made docstring corrections
a1aabfa	Merge branch '24848' into 24849

[sagetrac-git]

Changed commit from 2457e97 to a1aabfa

[fchapoton]

comment:8

if the Author field is empty, no patchbot will look at the ticket..

[jplab]

Author: Jean-Philippe Labbé

[jplab]

comment:9

My bad... too many tickets at the same time.

That's good to know!!

[sagetrac-git]

Changed commit from a1aabfa to ffe21e2

[sagetrac-git]

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

ffe21e2

Merge branch 'sage8.2.b7' into 24849

[fchapoton]

Reviewer: Frédéric Chapoton

[fchapoton]

comment:11

ok, let it be

[vbraun]

Changed branch from u/jipilab/24849 to ffe21e2