Stef Tijs (August 31, 1937 – June 13, 2023), or Stephanus Hendrikus Tjis was a Dutch mathematician and a

game theory Game theory is the study of mathematical models of strategic interactions. It has applications in many fields of social science, and is used extensively in economics, logic, systems science and computer science. Initially, game theory addressed ...

pioneer in

the Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

. He contributed to most subfields in game theory and particularly in

cooperative game theory In game theory, a cooperative game (or coalitional game) is a game with groups of players who form binding “coalitions” with external enforcement of cooperative behavior (e.g. through contract law). This is different from non-cooperative ...

, where he introduced the Tijs value (later known as the τ value) in 1981 as a solution to n-person games alternative to the

Shapley value In cooperative game theory, the Shapley value is a method (solution concept) for fairly distributing the total gains or costs among a group of players who have collaborated. For example, in a team project where each member contributed differently, ...

and others.

Education and career

Tijs was born in

Ginneken en Bavel Ginneken en Bavel was a municipality in the Dutch province of North Brabant, located southeast of the city of Breda. It covered the villages of Ginneken (now a neighbourhood of Breda) and Bavel. Ginneken en Bavel existed until 1942, when the vi ...

. He studied at

Utrecht University Utrecht University (UU; , formerly ''Rijksuniversiteit Utrecht'') is a public university, public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2023, it had an enrollment of ...

for a bachelor's degree in chemistry from 1954 to 1959, later he switched to mathematics, obtaining a MSc degree at the same university in 1963. Tijs was a research assistant in mathematics at

Radboud University Nijmegen Radboud University (abbreviated as RU, , formerly ) is a public university, public research university located in Nijmegen, Netherlands. RU has seven faculties and more than 24,000 students. Established in 1923, Radboud University has consistentl ...

from 1963 to 1969 and an assistant professor in mathematics there from 1969. He received his PhD in mathematics for work on

matrix games Matrix Games is a publisher of PC games, specifically strategy games and wargames. It is based in Ohio, US, and Surrey, UK. Their focus is primarily but not exclusively on wargames and turn-based strategy. The product line-up also includes sp ...

from the

under the supervision of Arnoud van Rooij and Freddy Delbaen (who was younger than Tijs) in 1975. He became an associate professor at Nijmegen in 1975 and gradually built up a Dutch school of game theory there with an international outlook. In 1982, Tijs initiated the game theory seminar in Nijmegen, which later prompted the Netherlands to join the European Meeting on Game Theory (also called SING) that is held annually from 2000. Tijs was promoted to full professor at

in 1985. In 1991, he moved to

Tilburg University Tilburg University is a Catholic research university specializing in the social and behavioral sciences, economics, law, business sciences, theology and humanities, located in Tilburg, Netherlands. Tilburg has a student population of about 19,1 ...

, where he became a professor at the Department of Econometrics and Operations Research and the Center of Economic Research. He stayed for the remainder of his career. Between 2003 and 2005, Tijs was also a professor of mathematics at

University of Genoa The University of Genoa () is a public research university. It is one of the largest universities in Italy and it is located in the city of Genoa, on the Italian Riviera in the Liguria region of northwestern Italy. The original university was fou ...

in Italy. Tijs received a honorary doctorate from the

Miguel Hernández University of Elche The Miguel Hernández University (''UMH'', , , ), is a Spanish Public University offering education, research and services facilitating the comprehensive development of its students. It is located in the province of Alicante (province), A ...

in 2000. He was a fellow and a council member of the

Game Theory Society The Game Theory Society (GTS) is a society for the promotion of research, teaching and application of game theory. It was founded in 1999 by Ehud Kalai and Robert Aumann and is registered in the Netherlands. Activities The GTS hosts a congress ...

. He became a Knight of the

Order of the Netherlands Lion The Order of the Netherlands Lion, also known as the Order of the Lion of the Netherlands (, ) is a Dutch honours system, Dutch order of chivalry founded by William I of the Netherlands on 29 September 1815. The Order of the Netherlands Lion wa ...

in 2003.

Bibliography

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References

{{DEFAULTSORT:Tijs, Stef 1937 births 2023 deaths People from North Brabant Game theorists 20th-century Dutch mathematicians Utrecht University alumni Radboud University Nijmegen alumni Academic staff of Radboud University Nijmegen Academic staff of Tilburg University Knights of the Order of the Netherlands Lion Academic staff of the University of Genoa