From: David Eppstein <eppstein@ics.uci.edu>
Subject: Re: Largest triangle among n points
Date: 4 Sep 2000 11:00:02 -0500
Newsgroups: comp.graphics.algorithms,sci.math.research
Summary: [missing]

In article <8ovmnu$naq$1@esel.cosy.sbg.ac.at>, gwesp@cosy.sbg.ac.at wrote:

>   given a set X of n points in the plane, determine the triangle 
>   with maximum circumference with vertices in X.

By "circumference" I guess you mean perimeter? This can be solved in
O(n log n) time: Aggarwal, A., Klawe, M. M., Moran, S., Shor, P., and 
Wilber, R. Geometric applications of a matrix-searching algorithm. 
Algorithmica 2 (1987), 195--208.
-- 
David Eppstein       UC Irvine Dept. of Information & Computer Science
eppstein@ics.uci.edu http://www.ics.uci.edu/~eppstein/