Paul Catlin 1948-1995

On April 20, 1995, Paul Allen Catlin passed away in Detroit, Michigan, at the age of 46, and the community of Graph Theory lost one of its best friends. Paul Catlin was born on June 25, 1948 in Bridgeport, Connecticut. His life-long love for mathematics was visible from the start. His younger brother, David Catlin, remembers Paul riding around on his tricycle counting for the sheer pleasure of knowing and using numbers [DC]. Paul’s fourth grade teacher, Mrs. Frew, recognized his talent and helped him learn trigonometry that year [JC]. At the age of 14, Paul designed an adding machine and built it from relays; only later did he learn that computers actually work on the principles he incorporated into his machine [JC,DC]. Paul attended the Grand Valley (Michigan) Summer Institute of Mathematics when he was 16. The next year he went to Arnold Ross’s NSF summer institute in number theory at the Ohio State University. This experience not only led directly to the contents of six of his rst seven papers, but also interested him enough in Ohio State that he returned there many years later for graduate work. But even before returning to Ohio State, while still an undergraduate student at Carnegie-Mellon University, he wrote his rst research paper (number [C1] in the publications list) and began his other number theory papers. Paul received his BA at Carnegie-Mellon University in 1970, and then returned to the Ohio State University, where he earned his MS in 1973 and Ph.D. in 1976. In about 1970 he rst became interested in Graph Theory, but that interest did not prevent his working on his number theory problems during his rst years at Ohio State. Indeed, Dijen Ray-Chaudhuri recalls him working late nights during his rst year there, doing his research [DR]. This work resulted in the papers numbered [C2–C4,C6,C7] in his publications list. However, Paul’s time was not spent only on study and research. He was rightly proud of his ability as a pool player. He was a reasonably good shot, and by using English on the cue ball, he could usually complete each shot with the cue ball in the location he wanted for his next shot. Once he kept a record of successive shots