Research output: Contribution to journal › Article › peer-review
STEFFEN’S FLEXIBLE POLYHEDRON IS EMBEDDED. A PROOF VIA SYMBOLIC COMPUTATIONS. / Александров, Виктор Алексеевич; Волокитин, Евгений Павлович.
In: Journal for Geometry and Graphics, Vol. 29, No. 1, 04.08.2025.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - STEFFEN’S FLEXIBLE POLYHEDRON IS EMBEDDED. A PROOF VIA SYMBOLIC COMPUTATIONS
AU - Александров, Виктор Алексеевич
AU - Волокитин, Евгений Павлович
PY - 2025/8/4
Y1 - 2025/8/4
N2 - A polyhedron is flexible if it can be continuously deformed preserving the shape and dimensions of every its face. In the late 1970’s Klaus Steffen constructed a sphere-homeomorphic embedded flexible polyhedron with triangular faces and with 9 vertices only, which is well-known in the theory of flexible polyhedra. At about the same time, a hypothesis was formulated that the Steffen polyhedron has the least possible number of vertices among all embedded flexible polyhedra without boundary. A counterexample to this hypothesis was constructed by Matteo Gallet, Georg Grasegger, Jan Legersk´y, and Josef Schicho in 2024 only. Surprisingly, until now, no proof has been published in the mathematical literature that the Steffen polyhedron is embedded. Probably, this fact was considered obvious to everyone who made a cardboard model of this polyhedron. In this article, we prove this fact using computer symbolic calculations.
AB - A polyhedron is flexible if it can be continuously deformed preserving the shape and dimensions of every its face. In the late 1970’s Klaus Steffen constructed a sphere-homeomorphic embedded flexible polyhedron with triangular faces and with 9 vertices only, which is well-known in the theory of flexible polyhedra. At about the same time, a hypothesis was formulated that the Steffen polyhedron has the least possible number of vertices among all embedded flexible polyhedra without boundary. A counterexample to this hypothesis was constructed by Matteo Gallet, Georg Grasegger, Jan Legersk´y, and Josef Schicho in 2024 only. Surprisingly, until now, no proof has been published in the mathematical literature that the Steffen polyhedron is embedded. Probably, this fact was considered obvious to everyone who made a cardboard model of this polyhedron. In this article, we prove this fact using computer symbolic calculations.
KW - Euclidean space
KW - flexible polyhedron
KW - embedded polyhedron
KW - symbolic computations
UR - https://arxiv.org/pdf/2508.02392
U2 - 10.48550/arXiv.2508.02392
DO - 10.48550/arXiv.2508.02392
M3 - Article
VL - 29
JO - Journal for Geometry and Graphics
JF - Journal for Geometry and Graphics
SN - 1433-8157
IS - 1
ER -
ID: 71522307