Opened 3 years ago

Last modified 22 months ago

#27086 closed enhancement

Simpliness and simpliciality for CombinatorialPolyhedron — at Version 7

Reported by: gh-kliem Owned by:
Priority: major Milestone: sage-9.1
Component: geometry Keywords: Polyhedron, CombinatorialPolyhedron, simple, simplicial, flag
Cc: jipilab Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: #26887 Stopgaps:

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Description (last modified by gh-kliem)

We add a function to CombinatorialPolyhedron that returns the largest k such that the polyhedron is k-simple/k-simplicial.

Change History (7)

comment:1 Changed 3 years ago by gh-kliem

  • Type changed from PLEASE CHANGE to enhancement

comment:2 Changed 3 years ago by gh-kliem

  • Description modified (diff)
  • Keywords flag added
  • Summary changed from Add simpliciality and simpliness to CombinatorialPolyhedron to More functions for CombinatorialPolyhedron

comment:3 Changed 3 years ago by gh-kliem

  • Description modified (diff)

comment:4 Changed 3 years ago by gh-kliem

Posting this example, so I won't forget:

An example for simpliness and simpliciality could look like this:

sage: for i in Combinations(6,3):
....:     x.append(list(Integer(j in i) for j in range(6)))
....: P = Polyhedron(vertices=x)
....: C = CombinatorialPolyhedron(P)
....: C.simpliness()
4
....: C.simpliciality()
2
....: C.dimension()
5

One can replace 6 by n and this will alter 4 to n-2 and 5 to n-1.

(This example is taken from lecture notes from Günter M. Ziegler.)

comment:5 Changed 3 years ago by embray

  • Milestone changed from sage-8.7 to sage-8.8

Ticket retargeted after milestone closed (if you don't believe this ticket is appropriate for the Sage 8.8 release please retarget manually)

comment:6 Changed 2 years ago by gh-kliem

  • Milestone changed from sage-8.8 to sage-wishlist

comment:7 Changed 2 years ago by gh-kliem

  • Description modified (diff)
  • Milestone changed from sage-wishlist to sage-9.0
  • Summary changed from More functions for CombinatorialPolyhedron to Simpliness and simpliciality for CombinatorialPolyhedron
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