The union of congruent cubes in three dimensions

János Pach, Ido Safruti, Micha Sharir

Research output: Contribution to journalArticlepeer-review

Abstract

A dihedral (trihedral) wedge is the intersection of two (resp. three) half-spaces in R3. It is called α-fat if the angle (resp., solid angle) determined by these half-spaces is at least α > 0. If, in addition, the sum of the three face angles of a trihedral wedge is at least γ > 4π/3, then it is called (γ, α-substantially fat. We prove that, for any fixed γ > 4π/3, α > 0, the combinatorial complexity of the union of n (a) α-fat dihedral wedges, and (b) (γ, α)-substantially fat trihedral wedges is at most O(n2+ε), for any ε > 0, where the constants of proportionality depend on ε, α (and γ). We obtain as a corollary that the same upper bound holds for the combinatorial complexity of the union of n (nearly) congruent cubes in R3. These bounds are not far from being optimal.

Original languageEnglish
Pages (from-to)133-160
Number of pages28
JournalDiscrete and Computational Geometry
Volume30
Issue number1
DOIs
StatePublished - Jul 2003

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