ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Sat, 06 Feb 2021 10:10:56 +0100Polyhedra, facets and verticeshttps://ask.sagemath.org/question/55597/polyhedra-facets-and-vertices/I have a 6-dimensional, convex, compact polyhedron in $\mathbb{R}^{12}$, that I am calling `P1`.
The polyhedron `P1` was specified by giving a large number of inequalities.
When I enter `P1.faces(5)` into Sage, I get the following
(A 5-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 6 vertices,
A 5-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 7 vertices,
A 5-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 7 vertices,
A 6-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 7 vertices,
A 5-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 6 vertices,
A 6-dimensional face of a Polyhedron in RDF^12 defined as the convex hull of 8 vertices,
...)
How can there be two 6-dimensional faces, each with a different number of vertices,
on the boundary of `P1`? I have checked that `P1` really does have dimension 6.
Also, when I try to find a list of vertices on the boundary of any 5-dimensional face of `P1`,
for example
P1.faces(5)[0].vertices_list()
I get an error message
AttributeError: 'tuple' object has no attribute 'vertices_list'
However, `P1.faces(5)[0].vertices()` works.
My second question is, how do I get a list of vertices on the boundary of an $n$-dimensional face?IngridSat, 06 Feb 2021 10:10:56 +0100https://ask.sagemath.org/question/55597/