Aarhus University Seal / Aarhus Universitets segl

Maximum overhang

Uri Zwick
(Tel Aviv University)
Fredag, 16 december, 2011, at 11:15-12:30, Peter Bøgh Andersen Auditoriet, Nygaard, Computer science

How far off the edge of the table can we reach by stacking n identical, homogeneous, frictionless blocks of length 1? A 150 year old solution to this problem of static mechanics achieves an overhang of H(n)/2, where H(n)=1/1+1/2+..+1/n is the n-th harmonic number. This solution was widely believed to be optimal. However, recent work of Mike Paterson, Yuval Peres, Mikkel Thorup, Peter Winkler and the speaker of today, Uri Zwick, shows that it is exponentially far from optimal.

Professor Uri Zwick from Tel Aviv University will present his work constructing simple n-block stacks that achieve an overhang of cn^(1/3), for some constant c>0. It is further shown that this is best possible, up to a constant factor.

This work won the David P. Robbins Prize of the MAA for an "outstanding paper in algebra, combinatorics, or discrete mathematics " and “The Lester R. Ford Award" of the MAA for "authors of articles of expository excellence published in The American Mathematical Monthly or Mathematics Magazine".