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20 votes
0 answers
433 views

Is the dodecahedron flexible (as a polytope with fixed edge-lengths)?

Consider the (regular) dodecahedron $D\subset\Bbb R^3$. I want to continuously deform it so that throughout the deformation it stays a convex polytope, it stays a combinatorial dodecahedron (i.e. its ...
M. Winter's user avatar
  • 13.6k
13 votes
0 answers
378 views

Is a convex polyhedron determined by its edge lengths and angular defects?

Let's consider 3-dimensional convex polyhedra $P\subset\Bbb R^3$. The angular defect at a vertex $v$ is $2\pi$ minus the sum of the interior angles of the incident faces at $v$. Question: Is a ...
M. Winter's user avatar
  • 13.6k
11 votes
1 answer
654 views

How to correctly state Cauchy's rigidity theorem?

Cauchy's rigidity theorem is often stated briefly as Any two (convex, 3-dimensional) polyhedra with pairwise congruent faces are themselves congruent. As a more formal generalization to general ...
M. Winter's user avatar
  • 13.6k
0 votes
0 answers
90 views

Which polytopes can be folded to an edge?

While playing with bar-and-joint linkages, I noticed that the skeleton of a regular 3-dimensional cube can be folded to a single edge (this can be achieved by first flexing the cube to bring it to a ...
Pritam Majumder's user avatar