# Questions tagged [abstract-polytopes]

An "abstract polytope" is a poset satisfying a list of properties shared by face lattices of polytopes.

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### Uniquely describing a polytopal complex by prescribing the local structure around its vertices

Let $C$ be a $d$-dimensional (abstract) polytopal complex. Most of what I say below could be asked in this general setting, but for a start, let's further restrict to simple polytopal spheres, that is,...
7answers
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### Why are we interested in permutahedra, associahedra, cyclohedra, …?

The following families of polytopes have received a lot of attention: permutahedra, associahedra, cyclohedra, ... My question is simple: Why? As I understand, at least the latter two were ...
1answer
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### Gluing simplices through a common point/ realisation of a convex simplicial polytope

Given $m≥d+1$ a positive integer, is it always possible to find m d-dimensional simplices $\Delta_i=\mathrm{Conv}(M,V_{i,1},…,V_{i,d})$ such that 1) they all share the common vertex M 2) the ...
3answers
405 views

### Minimal combinatorial data needed to define a polytope [duplicate]

Suppose I give a list of vertices $(v_1, v_2, ..., v_n)$, and a list of "adjacencies", i.e. pairs of vertices $(v_i,v_j)$. Does it exists a unique polytope that has this vertices and realises the ...
1answer
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### Is volume of abstract polytope realisation bounded by length of edges?

Suppose we have abstract polytope F of dimension d ( that is the greatest rank facet has rank n). Such abstract object may have realisations in d-dimensional Euclidean space as polytopes $A_i(F)$, and ...
2answers
180 views

### “Totally transitive” polytopes which are not regular

Is it possible to have an abstract polytope which is vertex-transitive, edge-transitive, face-transitive, etc. (individually transitive on faces of each particular dimension) and yet not flag-...
1answer
134 views

### Is a finite abstract polytope of Euler characteristic 0 Eulerian?

An abstract polytope is a poset $X$ (here finite), whose elements are called faces, satisfying these 4 conditions: There is a least face and a greatest face. All flags (i.e. maximal chains) have the ...
0answers
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### Question on abstract polytopes

Let $(P,\le)$ be an abstract $n$-polytope, with $n\ge 2$. Let $H,H',K$ be $m$-faces, with $0\le m \le n-2$. Is it true that there is a sequence $\{H_0=H,H_1,\ldots,H_{r-1},H_r=H' \} \subseteq P$ so ...
1answer
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### Criteria for abstract polytopes to be convex polytope

Suppose I have an abstract polytope defined by a poset. Are there any methods for determining whether the abstract polytope can be geometrically realized as convex-hull on its set of vertices?
2answers
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### Build a topological polytope with a specified CW-structure

I am a topologist and not quite familiar with the tools for building a polytope. I would like to build some topological polytope which is an somewhere in between permutohedron and associahedron which ...
1answer
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### Labeled polytopes

In a "problem of a week" contest in my school, I gave the following problem to students: we assign to each vertex of a cube a number $1$ or $-1$. And we associate to each face the product of the ...
1answer
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### What's the best way to test if a sphere is a polytope? (algorithms for the Simplicial Steinitz Problem)

The problem of recognizing whether a simplicial face lattice is polytopal is sometimes called the Steinitz problem. Sturmfels and Bokowski advanced a set of methods in the late 80s to test whether ...
2answers
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### Which finite groups are generated by n involutions?

One of the interesting problems in abstract polytope theory is to determine, for a given finite group, when that group is the automorphism group of a regular abstract polytope. This is equivalent to ...