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Permutations and Combination Locks

Award: Carl B. Allendoerfer

Year of Award: 1996

Publication Information: Mathematics Magazine, Vol. 68(1995), pp. 243-253

Summary: Counting the number of families of pairwise disjoint subsets of {1,2,...n}.

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About the Authors: (from Mathematics Magazine, Vol. 68 (1995)) Dan Velleman received his bachelor's degree from Darthmouth College in 1976 and his doctorate from the University of Wisconsin in 1980. He taught at the University of Texas and the University of Toronto before joining the faculty of Amherst College in 1983. He is interested in logic, philosophy of mathematics, and the foundations of quantum mechanics. He is author of the book How to Prove It, and a coauthor, with Joe Konhauser and Stan Wagon, of the forthcoming book Which Way Did the Bicycle Go?, a collection of problems from the problem-of-the-week series begun by Joe and continued by Stan.

A native of Hanover, N.H., Greg Call completed his A.B. degree at Dartmouth College in 1980. He did his graduate work at Harvard University under John Tate, receiving his Ph.D. in 1986. He taught for two years at Tufts University before going to Amherst College in 1988. While his primary research interests are Diophantine geometry and algebraic number theory, he is always ready to collaborate with Dan on an interesting problem-of-the-week.

Author (old format): 
Daniel J. Velleman and Gregory S. Call
Daniel J. Velleman and Gregory S. Call
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Publication Date: 
Friday, February 2, 2007
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Counting the number of families of pairwise disjoint subsets of {1,2,...n}