In and Out

In and Out offers readers an opportunity to ask questions of the experts.The Mathematica Journal encourages readers to submit problems in care of the editor.Answers posted to the Mathematica newsgroup, comp.soft-sys.math.mathematica,that appear here are edited for clarity and length. ‡ Working with IntervalsQ: A list of times of the form 88t 1 , t 1 + dt 1 <, 8t 2 , t 2 + dt 2 <, … , 8t n , t n + dt n << represents the periods 8t i , t i + dt i < when a particular system is not working.For two such lists, how can I determine the periods when both systems are not working?A: Carl Woll (carlw@wolfram.com)answers: The function timelist simulates nonoverlapping timing data of the form 88t 1 , t 1 + dt 1 <, 8t 2 , t 2 + dt 2 <, … , 8t n , t n + dt n <<.timelist@n_D := Function