Returning to Latvia, Grinbergs studied mathematics at the University of Latvia between 1930 and 1934. He graduated with distinction in 1934 and won the K Morbergs Stipend which gave him financial support to study abroad. During 1935 and 1936 he studied at the École Normale Supérieure in Paris. It was during his time in Paris that his first publication appeared; it was a work on geometry Über die Bestimmung von zwei speziellen Klassen von Eilinien Ⓣ. Returning to Riga, Grinbergs became a Privatdozent at the University of Latvia in 1937 and began his lecturing career in January 1938 teaching courses on geometry.
Political moves which would have a major impact on Grinbergs' career were soon happening; in particular the German-Soviet Nonaggression Pact was signed in August 1939 and Latvia's fate was out of its own hands. On 17 June 1940 the Red Army invaded Latvia and only three days later a new government of Soviet supporters was announced. They voted on 21 July for Latvia to become a part of the USSR and on 5 August this became official. The Soviet occupation saw around 35,000 Latvians deported to Russia within a year. During this extremely difficult period Grinbergs undertook research towards his thesis.
The German army invaded the USSR in July 1941. For a period Latvia was a province of a larger Ostland (including Estonia, Lithuania, and Byelorussia) and during this period, in 1943, Grinbergs defended his thesis On oscillations, superoscillations and characteristic points. Immediately following this Grinbergs was drafted into the German army. In 1944 the Soviet army again marched into Latvia and a renewed period of Soviet domination began. The fact that Grinbergs had served in the German army (he was forced to do so and he certainly did not wish to serve any army) did not find favour with the new Soviet rulers of Latvia and he was sent to a camp in Kutaisi, Georgia, in the Caucasus. The Soviets used his mathematical skills, for while he was there he solved computational problems concerning buildings.
In 1947 Grinbergs was allowed to return to Latvia, but he had to work in a factory involved in the manufacture of radios. He was not allowed to take up his post at the University of Latvia and his doctorate was declared void since it had been obtained during the period of German control of Latvia. Grinbergs soon began to apply his great mathematical skills to problems concerning radios. In particular he developed a theory for analysis and synthesis of linear electrical circuits, using the theory of approximation of functions to make electrical circuits easy to describe mathematically. By 1954 he was allowed to lecture at the University of Latvia and in 1956 he defended a second thesis (to replace the one declared void by the authorities) Problems of analysis and synthesis of simple linear circuits. In 1960 he was appointed as Head of a section in the Computer Centre at the University of Latvia. This Centre had been established in 1959 under the leadership of Eizens Arins and Arins, Grinbergs and Janis Daube were the main research leaders.
Grinbergs now led a group which undertook research into a number of different topics using computers. In particular :-
[a] significant achievement of Grinbergs' group was the development of analytic methods for calculation of planar contours of 3-dimensional components of the hulls of ocean going ships. These methods were highly acclaimed throughout the Soviet Union and were used by many shipbuilding companies.However he worked on a large number of topics, although he published relatively little. He developed a theory of splines, became interested in Markov processes, but also worked on graph theory which he loved more than any of the other topics. On his death in 1982 he left 20,000 pages of mathematical manuscript pages which he had never submitted for publication.
Dambitis gives this tribute to Grinbergs in :-
Emanuels Grinbergs ... was one of the greatest all-around mathematicians of the Baltics. Due to the isolation imposed by the former Soviet Union, most of his remarkable results and achievements are unknown in the Western world. It is therefore fitting that the first international graph theory conference in the Baltics should review the life and achievements of this remarkable scientist whose only fault was that he did things at the wrong time and was in the wrong place with respect to two of the most brutal totalitarian regimes that overran his country in 1940 (Stalin), 1941 (Hitler) and 1945 (Stalin again). Among his unpublished major achievements are a number of remarkable results in graph theory. He independently discovered spline theory to provide a method to form the hulls of ocean-going ships by cutting flat plates into shapes that after three-dimensional forming fitted together precisely enough for welding without further machining.
Article by: J J O'Connor and E F Robertson