Arnold Knopfmacher is a Professor of Mathematics at the University of the Witwatersrand, Johannesburg, where he also obtained his Ph.D. degree. His main research interests are in enumerative combinatorics and elementary number theory. He is Director of The John Knopfmacher Centre for Applicable Analysis and Number Theory, which was established in 1992 by his late father, a distinguished number theorist. Prior to John's death in 1999, Arnold and John collaborated extensively producing over thirty joint papers together.

Michael Mays is a Professor of Mathematics at West Virginia University, where he does research in combinatorics and number theory and develops software and course materials for the Institute for Math Learning. He has maintained his collaboration with Arnold Knopfmacher with five visits over the last decade to The John Knopfmacher Centre for Applicable Analysis and Number Theory at the University of the Witwatersrand.

Arnold Knopfmacher
The John Knopfmacher Centre for Applicable Analysis and Number Theory
University of the Witwatersrand
Johannesburg 2050, South Africa
arnoldk@cam.wits.ac.za
www.wits.ac.za/science/number_theory/arnold.htm

Michael Mays
Department of Mathematics
West Virginia University
Morgantown, WV 26506-6310
mays@math.wvu.edu
www.math.wvu.edu/~mays