Edgar Krahn ( – 6 March 1961) was an Estonian

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

. Krahn was born in Sootaga (now Laiuse,

Jõgeva County Jõgeva County ( et, Jõgeva maakond or ''Jõgevamaa'') is one of 15 counties of Estonia. It is situated in eastern part of the country and borders Ida-Viru County to the north-east, Lake Peipus to the east, Tartu County to the south, Viljandi C ...

Governorate of Livonia The Governorate of Livonia, also known as the Livonia Governorate, was a Baltic governorate of the Russian Empire, now divided between Latvia and Estonia. Geography The shape of the province is a fairly rectangular in shape, with a maximum ...

, as a member of the

Baltic German Baltic Germans (german: Deutsch-Balten or , later ) were ethnic German inhabitants of the eastern shores of the Baltic Sea, in what today are Estonia and Latvia. Since their coerced resettlement in 1939, Baltic Germans have markedly declined ...

minority. He died in

Rockville, Maryland Rockville is a city that serves as the county seat of Montgomery County, Maryland, and is part of the Baltimore–Washington metropolitan area. The 2020 census tabulated Rockville's population at 67,117, making it the fifth-largest community in ...

, United States. Krahn studied at the

University of Tartu The University of Tartu (UT; et, Tartu Ülikool; la, Universitas Tartuensis) is a university in the city of Tartu in Estonia. It is the national university of Estonia. It is the only classical university in the country, and also its biggest ...

and the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded ...

. He graduated at Tartu in 1918, received his

doctoral degree A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism '' ...

at Göttingen in 1926, with

Richard Courant Richard Courant (January 8, 1888 – January 27, 1972) was a German American mathematician. He is best known by the general public for the book '' What is Mathematics?'', co-written with Herbert Robbins. His research focused on the areas of r ...

as his advisor, and his

habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in many European countries. The candidate fulfills a university's set criteria of excellence in research, teaching and further education, usually including ...

took place at Tartu in 1928. He is co-author of the

Rayleigh–Faber–Krahn inequality In spectral geometry, the Rayleigh–Faber–Krahn inequality, named after its conjecturer, Lord Rayleigh, and two individuals who independently proved the conjecture, G. Faber and Edgar Krahn, is an inequality concerning the lowest Dirichlet eig ...

. Krahn worked in Estonia, Germany, the United Kingdom, and the United States in the following areas of pure and applied mathematics: *

Differential geometry Differential geometry is a mathematical discipline that studies the geometry of smooth shapes and smooth spaces, otherwise known as smooth manifolds. It uses the techniques of differential calculus, integral calculus, linear algebra and mult ...

Differential equations In mathematics, a differential equation is an equation that relates one or more unknown functions and their derivatives. In applications, the functions generally represent physical quantities, the derivatives represent their rates of change, an ...

* ''Bausparmathematik'', which is distantly related to insurance mathematics *

Probability theory Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set ...

Gas dynamics Compressible flow (or gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. While all flows are compressible, flows are usually treated as being incompressible when the Mach number (the ...

* Elasticity theory

References

{{DEFAULTSORT:Krahn, Edgar 1894 births 1961 deaths People from Jõgeva Parish People from the Governorate of Livonia Baltic-German people Estonian mathematicians 20th-century mathematicians 20th-century Estonian scientists University of Tartu alumni University of Göttingen alumni

See also

References