Kalman Gy ry is Professor Emeritus at the University of Debrecen, a member of the Hungarian Academy of Sciences and a well-known researcher in Diophantine number theory. Over his career he has obtained several significant and pioneering results, among others on unit equations, decomposable form equations, and their various applications. His results have been published in one book and 160 research papers. Gy ry is also the founder and leader of the Number Theory Research Group in Debrecen, which consists of his former students and their descendants.