On the Complexity of Computing the Measure of U[ai, bi] The decision tree complexity of computing the measure of the union of n (possibly overlapping) intervals is shown to be (n log n), even if comparisons between linear functions of the interval endpoints are allowed. The existence of an (n log n) lower bound to determine whether any two of n real numbers are within of each other is also demonstrated. These problems provide an excellent opportunity for discussing the effects of the computational model on the ease of analysis and on the results produced. CACM July, 1978 Fredman, M. Weide, B. Analysis of algorithms, combinatorial problems, computational complexity, computational models, decision tree programs, lower bounds 5.25 5.26 5.30 5.39 CA780702 DH February 8, 1979 3:46 PM 3086 5 3086 3086 5 3086 3086 5 3086