On Tue, Nov 30, 2010 at 6:33 PM, Roberto Ierusalimschy <roberto@inf.puc-rio.br> wrote: > Something like linterval? > (http://www.tecgraf.puc-rio.br/~lhf/ftp/lua/#linterval) Yes, that's exactly it. The source of all wisdom has some very readable paragraphs: http://en.wikipedia.org/wiki/Interval_arithmetic