ar X iv : c s . C C / 9 90 60 08 v 1 4 J un 1 99 9 Average - Case Complexity of Shellsort

ar X iv : c on d - m at / 9 60 31 90 v 1 2 9 M ar 1 99 6 The Four - Dimensional XY Spin Glass

ar X iv : c s . C G / 9 90 70 25 v 1 1 6 Ju l 1 99 9 The union of unit balls has quadratic complexity , even if they all contain the origin

We provide a lower bound construction showing that the union of unit balls in R has quadratic complexity, even if they all contain the origin. This settles a conjecture of Sharir.

ar X iv : h ep - l at / 9 90 60 02 v 1 1 J un 1 99 9 Exploring the π + – π + Interaction in Lattice QCD

ar X iv : c on d - m at / 9 80 60 82 v 1 [ co nd - m at . m tr l - sc i ] 5 J un 1 99 8 Magnetic Particles

ar X iv : c s / 99 08 00 6 v 1 [ cs . C G ] 1 1 A ug 1 99 9 Computational Geometry Column 36

Two results in “computational origami” are illustrated. Computational geometry has recently been applied to solve two open problems in “origami mathematics.”