Alexei Pokrovskii:ALEXEI POKROVSKII, who has died aged 62, was an eclectic mathematician, occupied the Chair of Applied Mathematics at University College, Cork, for the past nine years.
He was born and reared in Voronezh, a city in central Russia about 500km south of Moscow. Both his father and paternal grandfather were professors at Voronezh Medical Academy, while his mother was a teacher of English.
He started publishing original mathematics while still a teenager, and Voronezh State University, founded in 1918, conferred the degrees of BSc and MSc on him.
In 1969 he moved to Moscow with his supervisor Mark Krasnosel’skii – one of Russia’s foremost mathematicians of the last century – where he completed his PhD in 1974.
He had a long and productive collaboration with Krasnosel'skii. Inter alia, they created a mathematical theory of hysteresis, which led to the publication in 1983 of their book Systems with hysteresis, a seminal work, that was later translated into English.
That same year he was awarded the prestigious Andronov Prize by the Russian Academy of Sciences. In 1989, he obtained his Dr Sci at the Institute for Control Problems, Russian Academy of Sciences.
Until he emigrated with his family to Australia in 1992, Alexei remained in Moscow, conducting research at the Institute for Information Transmission Problems. His research collaboration with academicians there was wide-ranging and prolific.
For the period of his stay in Australia during 1993-1997, Alexei divided his time between Deakin University, Geelong, and the University of Queensland, Brisbane. Although he did not have security of tenure at either place, nevertheless, the time spent in Australia was a productive one for him, and a happy time for his family, who retain fond memories of their stay.
Alexei first came to Cork in the spring of 1997 to be interviewed for the Chair of Applied Mathematics at UCC. As part of the interview process, he delivered a lecture about his research interests, using the opportunity to pay tribute to his mentor and teacher, Mark Krasnosel’skii, who had just died.
Later that day he gave an impromptu talk to members of the student Mathematical Society, captivating them with a selection of witty problems, such as: how should Vladimir in Leningrad mail a gold ring to his beloved Irene in Moscow knowing that any letter or parcel, thought to contain something valuable, would be opened as it passed through the Russian postal system, and its contents stolen?
He also offered a bottle of wine to the first student who could solve this problem: Is it possible to place 26 non-overlapping unit squares in a square of side 5.1 units? (These are metaphors for important everyday problems.)
While his bid for the chair wasn’t successful, he accepted an offer of a research position in the Institute of Non-linear Science in UCC. This post, though not a permanent one, provided a modicum of security for himself and his family. It enabled him to display his expertise in several branches of mathematics, and his capacity to interact productively with experts in other areas of science.
It became manifest that he was a polymath of the first rank. Accordingly, when it was vacated again, it came as no surprise when he was appointed to the chair in 2001.
He was an indefatigable researcher, and following his appointment, while he continued to work with people outside UCC, he developed fruitful collaborations with members in his own department, and in UCC’s departments of Computer Science, Civil, Electrical and Food Engineering, Mathematics, Microbiology, Statistics, Physics, and Zoology.
He had a child-like curiosity and wonderment for the scientific world, a knowledge of several disparate areas which, combined with a penetrating mind, enabled him to apply mathematical advances to them in a host of different ways and make significant progress in whatever problem took his interest.
But he also took a keen interest in other people’s work and whenever somebody shared a surprising new fact with him, his eyes would light up, and one would get the thumbs up sign, signifying his delight. Such a response was very encouraging to the person sharing the information, and especially bolstered the confidence of a young researcher. He was immensely generous with his time and talents, and warm-hearted in attributing to others ideas that very often were his alone.
From the beginning, Alexei took an active interest in UCC’s mathematics enrichment programme. He often devoted his Saturday mornings to enthral school students with applications of the “pigeon-hole principle”: If a postman delivers 101 letters to 100 houses, then at least one house receives two or more letters.
This simple principle is illustrative of the kind of research problem that was close to his heart, namely, an existence problem, the sort of problem faced, for instance, by a brain surgeon who wants to be able to detect the presence and size of a tumour without opening the skull, a problem that has a mathematically-based solution.
During his headship, Alexei organised several conferences on hysteresis, multi-rate processes and dynamical systems. These attracted specialists in diverse disciplines from many parts of the world, and established his department as a centre of research excellence.
He was knowledgeable about a range of subjects: for instance, he could discuss the impact The Gadflyby Ethel Voynich, a Cork woman, made in Russia, and compare Kandinsky's art work with that of Klee.
Alexei was a mathematical genius, whose published articles exceeded 200. He had a special way with people, both young and old, and was loved by everyone who knew him.
He is survived by his wife Natasha, his daughter Olya, son Alosha and sister Olga.
Alexei Vadimovich Pokrovskii: born June 2nd, 1948, died September 1st, 2010