A line ℓ is a transversal to a family F of convex polytopes in ℝ3 if it intersects every member of F. If, in addition, ℓ is an isolated point of the space of line transversals to F, we say that F is a pinning of ℓ. We show that any minimal pinning of a line by polytopes in ℝ3 such that no face of a polytope is coplanar with the line has size at most eight. If in addition the polytopes are pairwise disjoint, then it has size at most six.
Joint work with Boris Aronov, Otfried Cheong, and Günter Rote.
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