Paul A. Catlin

Paul Allen Catlin (June 25, 1948 – ) was a mathematician, professor of mathematics who worked in graph theory and number theory. He wrote a significant paper on the series of chromatic numbers and Brooks' theorem, titled  Hajós graph coloring conjecture: variations and counterexamples.

Career
Originally from Bridgeport, Connecticut, Catlin majored in Mathematics with a B.A. degree from Carnegie Mellon University in 1970.

Catlin held a Doctorate in Mathematics degree from Ohio State University. From 1972 to 1973, he was a research and teaching assistant at Ohio State University, where he earned the Master of Science degree in Mathematics.

In 1976, he went to work at Wayne State University, where he concentrated the research on chromatic numbers and Brooks' theorem. As a result, Catlin published a significant paper in that series: Hajós graph coloring conjecture: variations and counterexamples., which showed that the conjecture raised by Hugo Hadwiger is further strengthened not only by $$ k \le 4 $$ but also by $$ k \ge 7 $$, which led to the joint paper written with Paul Erdős and Béla Bollobás titled Hadwiger's conjecture is true for almost every graph.

He authored over fifty academic papers in number theory and graph theory. Many of his contributions and collaborations have been published in The Fibonacci Quarterly, in The Journal of Number Theory, in the Journal of Discrete Mathematics, and many other academic publications. He co-authored scholarly papers with Arthur M. Hobbs, Béla Bollobás and Paul Erdős, Hong-Jian Lai, Zheng-Yiao Han, and Yehong Shao, among others. He also published papers with G. Neil Robertson, with whom he also completed his dissertation thesis in 1976.