Marinus Adriaan "Rien" Kaashoek (November 10, 1937 – November 21, 2024) was a Dutch mathematician, and Emeritus Professor Analysis and Operator Theory at the

Vrije Universiteit The (abbreviated as ''VU Amsterdam'' or simply ''VU'' when in context) is a public research university in Amsterdam, Netherlands, founded in 1880. The VU Amsterdam is one of two large, publicly funded research universities in the city, the othe ...

in Amsterdam.

Biography

Born in

Ridderkerk Ridderkerk () is a town and municipality in the western Netherlands, in the province of South Holland. The municipality had a population of in and covers an area of of which is covered by water. The municipality of Ridderkerk also includes th ...

, Kaashoek has studied mathematics at the

Leiden University Leiden University (abbreviated as ''LEI''; ) is a Public university, public research university in Leiden, Netherlands. Established in 1575 by William the Silent, William, Prince of Orange as a Protestantism, Protestant institution, it holds the d ...

, where he received his PhD in 1964 under supervision of Adriaan Zaanen. Kaashoek had started his academic career as assistant at the

from 1959 to 1962, and Junior Staff Member from 1962 to 1965. In 1966 he started as senior lecturer at the

, where in 1969 he was appointed professor. Among his doctoral students is Harm Bart (1973). Kaashoek has been at the

University of Maryland, College Park The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public university, public Land-grant university, land-grant research university in College Park, Maryland, United States. Founded in 1856, UMD i ...

in 1975, at the

University of Calgary {{Infobox university , name = University of Calgary , image = University of Calgary coat of arms without motto scroll.svg , image_size = 150px , caption = Coat of arms , former ...

in 1987, at the

Ben-Gurion University of the Negev Ben-Gurion University of the Negev (BGU) (, ''Universitat Ben-Guriyon baNegev'') is a public university, public research university in Beersheba, Israel. Named after Israeli List of national founders, national founder David Ben-Gurion, the unive ...

in 1987 and at the

Tel Aviv University Tel Aviv University (TAU) is a Public university, public research university in Tel Aviv, Israel. With over 30,000 students, it is the largest university in the country. Located in northwest Tel Aviv, the university is the center of teaching and ...

on various occasions. He was a member of the honorary editorial board of the Journal ''Integral Equations and Operator Theory,'' and has been appointed Knight in the

Order of the Dutch Lion The Order of the Netherlands Lion, also known as the Order of the Lion of the Netherlands (, ) is a Dutch order of chivalry founded by William I of the Netherlands on 29 September 1815. The Order of the Netherlands Lion was until recently awar ...

(Ridder in de Orde van de Nederlandse Leeuw) in 2002. In 2014 he received an honorary doctorate of

North-West University The North-West University (NWU) is a public research university located on three campuses in Potchefstroom, Mahikeng and Vanderbijlpark in South Africa. The university came into existence through the merger in 2004 of the Potchefstroom Univer ...

in South-Africa (Potchefstroom campus). He was elected honorary member (erelid) of the Royal Dutch Mathematical Society ( Koninklijk Wiskundig Genootschap) on 22 March 2016. M. A. Kaashoek was one of the early supporters of the

International Workshop on Operator Theory and its Applications International Workshop on Operator Theory and its Applications (IWOTA) was started in 1981 to bring together mathematicians and engineers working in operator theoretic side of functional analysis and its applications to related fields. These inc ...

( IWOTA), which was started in 1981. From the beginning, M. A. Kaashoek and J. W. Helton served as vice presidents of the IWOTA Steering Committee. In addition, M. A. Kaashoek organized the third IWOTA in 1985, the first time this series of conferences took place in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. Moreover, he maintained a website documenting the complete IWOTA series. Kaashoek died on November 21, 2024, at the age of 86.

Work

Kaashoek's research interests are in the field of 'the "analysis and Operator Theory, and various connections between Operator Theory, Matrix Theory and Mathematical Systems Theory. In particular, Wiener–Hopf integral equations and Toeplitz operators, their nonstationary variants, and other structured operators, such as continuous operator analogs of Bézout and resultant matrices. State space methods for problems in analysis. Also metric constrained interpolation problems and completion problems for partially given operators, including relaxed commutant lifting problems."

Publications

Kaashoek has authored and co-authored ten booksBooks co-authored by M.A. Kaashoek
at cs.vu.nl. Accessed September 11, 2013 A selection: * 1974. ''Locally compact semi-algebras : with applications to spectral theory of positive operators''. With

Trevor West Timothy Trevor West (8 May 1938 – 30 October 2012) was an Irish mathematician, academic and politician. Biography He was born on 8 May 1938 in County Cork, the eldest of four sons of Timothy Roberts West, headmaster of Midleton College, and ...

. Amsterdam; London : North-Holland Publishing Co. * 1993. ''Classes of linear operators, Volume 1 and 2.'' With

Israel Gohberg Israel Gohberg (; ; 23 August 1928 – 12 October 2009) was a Bessarabian-born Soviet and Israeli mathematician, most known for his work in operator theory and functional analysis, in particular linear operators and integral equations. Biograph ...

and Seymour Goldberg. Birkhäuser. * 2003. ''Basic classes of linear operators.'' With

and Seymour Goldberg. Springer. Articles, a selection: * Harm Bart, et al. "Factorizations of transfer functions." SIAM Journal on Control and Optimization 18.6 (1980): 675–696. *

and Marinus Adriaan Kaashoek. "Time varying linear systems with boundary conditions and integral operators. I. The transfer operator and its properties." Integral Equations and Operator Theory 7.3 (1984): 325–391.

References

External links

Rien Kaashoek
at the Vrije Universiteit {{DEFAULTSORT:Kaashoek, Rien 1937 births 2024 deaths Dutch mathematicians Academic staff of Leiden University Academic staff of Vrije Universiteit Amsterdam People from Ridderkerk Knights of the Order of the Netherlands Lion