Linards Reizins family, including his father Eduard Reizins, were teachers. He attended elementary school in Riga and from there he Second Gymnasium of Riga but World War II began before these were completed.
Latvia had been dominated by Russia from the end of the 18th century until World War I. During 1917 this domination ended and, after a brief period of German invasion, the country became independent in a proclamation made on 18 November 1918. It was into this independent Latvia that Reizins was born and brought up, but that independence ended while he was still at high school. 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 Reizins continued his studies at the Gymnasium in Riga. However, the German army invaded Latvia in July 1941.
Reizins had been attending a sport camp at Burtnieki Lake in the north of the country when the German armies entered Riga. The roads to the capital were blocked so Reizins, together with other young men from the Second Gymnasium who had been at the camp, went first to Valmiera about 40 km south of Burtnieki, then they decided to head north towards Estonia. Crossing the border they continued to head north until they reached Paide which is over half way to Tallin from the Latvian-Estonian border. In Paide they were caught by the German armies continuing to advance rapidly across Estonia. The group of young men scattered in their attempt to avoid being detained by the Germans, but Reizins was taken prisoner and returned to Riga which was now under German control.
In the Spring of 1942 the Germans released Reizins and allowed him to complete the final high school examinations which he had been unable to take previously. However he desperately wanted to avoid being drafted into the German army so he looked for the right sort of job. He worked in the countryside in the summer, trained to be a physical education teacher and had a job with a telephone company, but, despite this, near the end of the war he was forced into hiding to avoid being drafted.
In 1944 the Soviet army marched into Latvia and a renewed period of Soviet domination began. Reizins was now able to enter the University of Latvia in Riga where he studied mathematics. He was highly successful in his mathematical studies and also took a full part in university life, including sport which he greatly enjoyed. He graduated in 1948 with distinction and became a member of the Department of Mathematical Analysis at the University while he undertook research on differential equations under Arvids Lusis.
If Reizins had fared badly under the German occupation of Latvia, he did not fare much better under the Soviet domination, for in 1949 he lost his position at the University. The regime aimed to transform the country into a typical Soviet one, and many native Latvians were deported and Russians brought in to help achieve this. Reizins was forced to take a job as a secondary school teacher. For ten years he was employed at Riga Secondary School No 7 where he taught mathematics and became the assistant headmaster. However, he continued to undertake research in mathematics and in 1951 his first paper The behaviour of the integral curves of a system of three differential equations in the neighbourhood of a singular point was published by the Latvian Academy of Sciences. An English translation was published by the American Mathematical Society in 1955.
In 1958 Reizins was able to take up the lectureship in mathematics at the University of Latvia which he had been dismissed from in 1948. In the following year he defended his thesis The behaviour of trajectories in the neighbourhood of a stationary point in the three-dimensional space at Tartu State University. In this :-
... thesis he studied the qualitative behaviour of homogeneous differential equations and obtained results that were highly regarded by specialists.
Reizins was promoted to associate professor at the University of Latvia in 1969 and ten years later to full professor. He also worked at the Latvian Academy of Sciences, being appointed as a junior research fellow at the Astronomy Department in 1957. He was promoted to Scientific Secretary in the following year, then years later to Senior Research Fellow. In 1963 he became Head of the Department of Mathematics at the Institute of Physics of the Latvian Academy of Sciences. The Academy had no Institute of Mathematics and Reizins campaigned for years for the establishment of such an Institute.
Of the many other important contributions made by Reizins we should mention in particular his work on Pfaff's equations and his contributions to the history of mathematics. In particular he edited the Complete Works of Piers Bohl which was published in 1974. Other important historical papers include Mathematics in University of Latvia 1919-1969 (1975, joint with E Riekstins) and From the History of the General Theory of Ordinary Differential Equations (1977).
Article by: J J O'Connor and E F Robertson