Migrate `is_lawrence_polytope` and `is_pyramid` to combinatorial polyhedron

[kliem]

This ticket migrates the methods is_lawrence_polytope and is_pyramid from Polyhedron_base to CombinatorialPolyhedron.

Also, we change the output for the 0-dimensional polyhedron. It is a pyramid over the empty polyhedron, even if it is not constructable in sage.

Along the way we fix a small bug, where the trivial combinatorial polyhedron in dimension 0 was set up without vertices (and facets). The bug fix is tested by CombinatorialPolyhedron(0).is_pyramid(certificate=True).

CC: @jplab @LaisRast

Component: geometry

Keywords: pyramid, lawrence polytope, combinatorial polyhedron

Author: Jonathan Kliem

Branch/Commit: 7e25b29

Reviewer: Laith Rastanawi

Issue created by migration from https://trac.sagemath.org/ticket/29189

[kliem]

New commits:

364a796	migrate is_pyramid to combinatorial polyhedron
3af855d	migrate is_lawrence_polytope to combinatorial polyhedron

[kliem]

Branch: public/29189

[kliem]

Commit: 3af855d

[sagetrac-git]

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

db79f1e

little improvement

[sagetrac-git]

Changed commit from 3af855d to db79f1e

[kliem]

Changed branch from public/29189 to public/29189-reb

[kliem]

Changed commit from db79f1e to c47fc68

[kliem]

New commits:

04cd0cf	migrate is_pyramid to combinatorial polyhedron
7cf6c20	migrate is_lawrence_polytope to combinatorial polyhedron
da9e835	little improvement
c47fc68	applied changes from 28608

[LaisRast]

comment:4

Seems good to me.
Is there a reason why you do not put is_pyramid as a cached method?

[kliem]

Changed commit from c47fc68 to 77433d7