Our professors Ilie Popa (1907  1983) On the 20th of July we celebrated 90 years since the birth of Professor Ilie Popa, the famous professor of the Faculty of Mathematics within the University of Iasi, an outstanding teacher for over 40 generations of students. He was born in Iasi, a city to which he felt profoundly connected and where he carried out most of his professional activity. He accomplished his education in his native city beginning with the primary school till his brilliant university graduation in 1931, making himself known as a distinguished student, with outstanding capacities for original creation. Due to his exceptional qualities, he was accepted by the Faculty of Science of Iasi University as Assistant professor and began his research activity under the guidance of Professor Al. Myller. In 1932 he published his first two articles  on geometry  together with Mendel Haimovici, another distinguished professor and man of science from the Iasi Faculty of Mathematics. In 1934 he presented his Ph.D. thesis on differential geometry titled "Contributions to CentroAffine Differential Geometry", which had been inspired by the research undertaken by his two mentors Al. Myller and O. Mayer. In the period 19361938 the Romanian Academy offered him a scholarship in Rome and Hamburg, on which occasion he had as tutors Enrico Bompiani in Italy and Wilhelm Blaschke in Germany. During his stay abroad he was promoted as Associate Professor in the Superior Algebra Department within the Faculty of Science, Iasi University. In 1942 he became Professor at "Gh. Asachi" Polytechnic Institute of Iasi, and later that year he was transferred at the Faculty of Science of "Al.I. Cuza" University. In 1948 he became the Head of the newly opened Mathematical Analysis Department within the Faculty of Mathematics in Iasi, a position that he held until his retirement in 1973. After his retirement he continued working as consultant professor, until 1977, for the department he had led competently and efficiently for 25 years. Professor I. Popa's extended research activity was materialized in almost 100 published or presented papers of great significance in the fields of Differential Geometry, Mathematical Analysis and the History of Mathematics, each of them meaning substantial contributions in the fields. His results on Differential Geometry (he published about 40 articles, some of them together with the professors Al. Myller, M. Haimovici or Gh. Gheorghiev) join the studies of the school of geometry in Iasi led by the academicians Al. Myller and O. Mayer. These results were intensely quoted by famous mathematicians as B. Segre, S. Finikov, G. Bohl, O. Boruvka and others. Equally in the field of Geometry he obtained interesting results in Global Geometry, refining some previous results of the renowned mathematicians Fréchet, Mayward, Bottema or Meissner; he already uses here some fine methods of real analysis, which he impressed by some results of great fineness such as the statement of sufficient conditions for a real function not to be Lebesgue measurable. In the History of Mathematics, Professor Ilie Popa published a great number of studies proving that, besides being a keen researcher, he was also a gifted historiographer of Romanian mathematics. Among his studies we would like to refer to those in which he highlighted the Italian sources of the first Moldavian book of arithmetic, written in 1795 by Amfilohie Hotinul, simultaneously emphasizing the contribution to the beginning of the Romanian mathematical scientific terminology. Also we refer to those where he emphasized the contributions made by some precursors in the field of Mathematics, such as Dimitrie Asachi, Nicu Botez or Dimitrie Isopescul. If as a scholar Professor Ilie Popa was known as a profound and fine mathematician, as a teacher he was considered of a mathchless pedagogical mastership. All who were his students keep intensely in our memory his wonderful lessons, which constituted true models hard to be equalized by his disciples. We were fascinated by the beauty and the elegance of his discourse, by the crystal clarity of his argumentations reasonings, by the manner in which he knew to make himself understood by all who attended his classes, without the least compromise to the perfect rigor of his exposition. He knew, like no one else before, to conceive his lectures and seminars in such a way that it created the impression that the participants were directly involved in the discovery of those notions or results. He was an accomplished pedagogue, a fine psychologist, a good adviser and the embodiment of perfect discreetness. During the 20 years that I worked with him  as student and collaborator  I never heard him say anything offensive or humiliating. His remarks were always made in a kind and worm tone, without meanness, directed to the sensibility of the person who had made a mistake, so that he or she would never be able to repeat it. With tact and patience he guided and advised generations of students. Many of his lectures and conferences were addressed to pupils, students and high school teachers, contributing thus to the modernization of the teaching of mathematics, as well as to the fame of Iasi Faculty of Mathematics and the Mathematics Seminar. During more than 40 years dedicated to the mathematical teaching, professor Ilie Popa held various positions in the academic community. Thus, apart the position of Head of the Mathematical Analysis Department, which he maintained for 25 years, he was also the ViceRector of Iasi University for two legislations, Rector of the Pedagogical Institute of Iasi between 1961 and 1964, General Director of the Ministry of Education, all enabling him to have essential contributions to the improvement of Romanian gymnasium and university education. For 10 years he also held the honorary position as Director of the Mathematics Seminar succeeding to the academician Al. Myller  the founder of the Mathematics Seminar which today is named after him. Professor Ilie Popa was a multilateral personality, representing an example of life and work devoted to the Romanian education. For those who knew him, for his students and collaborators, Professor Ilie Popa is a model of the sense of duty, of a passioned researcher, and of an accomplished master.
