Germund Dahlquist (16 January 1925 – 8 February 2005) was a Swedish

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 ...

known primarily for his early contributions to the theory of

numerical analysis Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of numerical methods ...

as applied to

differential equation 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, ...

s. Dahlquist began to study mathematics at

Stockholm University Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, ...

in 1942 at the age of 17, where he cites the Danish mathematician Harald Bohr (who was living in exile after the

occupation of Denmark At the outset of World War II in September 1939, Denmark declared itself neutral. For most of the war, the country was a protectorate and then an occupied territory of Germany. The decision to occupy Denmark was taken in Berlin on 17 Decem ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

) as a profound influence. He received the degree of licentiat from Stockholm University in 1949, before taking a break from his studies to work at the Swedish Board of Computer Machinery ( Matematikmaskinnämnden), working on (among other things) the early computer BESK, Sweden's first. During this time, he also worked with

Carl-Gustaf Rossby Carl-Gustaf Arvid Rossby ( 28 December 1898 – 19 August 1957) was a Swedish-born American meteorologist who first explained the large-scale motions of the atmosphere in terms of fluid mechanics. He identified and characterized both the jet ...

on early numerical weather forecasts. Dahlquist returned to Stockholm University to complete his Ph.D., ''Stability and Error Bounds in the Numerical Solution of Ordinary Differential Equations'', which he defended in 1958, with Fritz Carlson and

Lars Hörmander Lars Valter Hörmander (24 January 1931 – 25 November 2012) was a Swedish mathematician who has been called "the foremost contributor to the modern theory of linear partial differential equations". Hörmander was awarded the Fields Med ...

as his advisors. As part of this work he introduced the logarithmic norm (also introduced by Russian mathematician

Sergei Lozinskii Sergius is a male given name of Ancient Roman origin after the name of the Latin ''gens'' Sergia or Sergii of regal and republican ages. It is a common Christian name, in honor of Saint Sergius, or in Russia, of Saint Sergius of Radonezh, and ...

the same year). In 1959 he moved to the

Royal Institute of Technology The KTH Royal Institute of Technology ( sv, Kungliga Tekniska högskolan, lit=Royal Institute of Technology), abbreviated KTH, is a public research university in Stockholm, Sweden. KTH conducts research and education in engineering and technolog ...

(KTH), where he would later establish what became the Department of Numerical Analysis and Computer Science (NADA) in 1962 (now part of the School of Computer Science and Communication), and become Sweden's first Professor of Numerical Analysis in 1963.NADA History
/ref> He helped establish the Nordic journal of numerical analysis, BIT, in 1961. In 1965 he was elected into the

Royal Swedish Academy of Engineering Sciences The Royal Swedish Academy of Engineering Sciences or ''Kungliga Ingenjörsvetenskapsakademien'' (IVA), founded on 24 October 1919 by King Gustaf V, is one of the royal academies in Sweden. The academy is an independent organisation, which prom ...

(IVA). The software package

COMSOL Multiphysics COMSOL Multiphysics is a finite element analysis, solver, and simulation software package for various physics and engineering applications, especially coupled phenomena and multiphysics. The software facilitates conventional physics-based us ...

, for

finite element analysis The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat ...

partial differential equations In mathematics, a partial differential equation (PDE) is an equation which imposes relations between the various partial derivatives of a multivariable function. The function is often thought of as an "unknown" to be solved for, similarly to ...

, was started by a couple of Dahlquist's graduate students based upon codes developed for a graduate course at KTH.

Honors and awards

SIAM Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

1988 John von Neumann lecturer. * SIAM 1991 Peter Henrici Prize. * SIAM Germund Dahlquist Prize, established 1995, "Awarded to a young scientist (normally under 45) for original contributions to fields associated with Germund Dahlquist, especially the numerical solution of differential equations and numerical methods for scientific computing". *Three honorary doctorates, from

Hamburg Hamburg (, ; nds, label=Hamburg German, Low Saxon, Hamborg ), officially the Free and Hanseatic City of Hamburg (german: Freie und Hansestadt Hamburg; nds, label=Low Saxon, Friee un Hansestadt Hamborg),. is the List of cities in Germany by popul ...

(1981),

Helsinki Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and towns in Finland, most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of U ...

(1994), and

Linköping Linköping () is a city in southern Sweden, with around 105,000 inhabitants as of 2021. It is the seat of Linköping Municipality and the capital of Östergötland County. Linköping is also the episcopal see of the Diocese of Linköping (Church ...

(1996).

Notes

{{DEFAULTSORT:Dahlquist, Germund Numerical analysts 20th-century Swedish mathematicians KTH Royal Institute of Technology faculty 1925 births 2005 deaths Stockholm University alumni

See also

Honors and awards

Notes