mathematics

Roger J-B Wets

Roger J-B Wets is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Roger J-B Wets rather than just read about it. In short: Roger Jean-Baptiste Robert Wets (February 1937 – April 1, 2025) was a Belgian stochastic programming and a leader in variational analysis who published as Roger J-B Wets. His research, expositions, graduate students, and his collaboration with R.

Key takeaways

Roger J-B Wets belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Roger J-B Wets to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Roger J-B Wets from memory before moving on to harder problems.

Reference excerpt

Roger Jean-Baptiste Robert Wets (February 1937 – April 1, 2025) was a Belgian stochastic programming and a leader in variational analysis who published as Roger J-B Wets. His research, expositions, graduate students, and his collaboration with R. Tyrrell Rockafellar have had a profound influence on optimization theory, computations, and applications. Since 2009, Wets has been a distinguished research professor at the mathematics department of the University of California, Davis.

Schooling and positions Roger Wets attended high school in Belgium, after which he worked for his family while earning his Licence in applied economics from Université de Bruxelles (Brussels, Belgium) in 1961. He was encouraged by Jacques H. Drèze to study optimization with George Dantzig at the program in operations research at the University of California, Berkeley. Dantzig and mathematician–statistician David Blackwell jointly supervised Wets's dissertation. In 1965 Wets befriended R. Tyrrell Rockafellar, whom Wets introduced to stochastic optimization, starting a collaboration of many decades.

He worked at Boeing Scientific Research Labs, 1964–1970 and was Ford Professor at the University of Chicago, 1970–1972 before being appointed Professor at the Mathematics Department of the University of Kentucky and then University Research Professor (1977–78). While at the International Institute for Applied Systems Analysis (IIASA) in Austria, during 1980–1984, he led research in decision-making in uncertainty, returning as an acting leader in 1985–1987; during that time, Wets and Rockafellar developed the progressive-hedging algorithm for stochastic programming. The University of California, Davis named him Professor (1984–1997), Distinguished Professor, and Distinguished Research Professor of Mathematics (2009–).

Awards and contributions

Wets was awarded a George B. Dantzig Prize for "original research that has had a major impact on the field of mathematical programming" by the Society for Industrial and Applied Mathematics (SIAM) and the Mathematical Programming Society (MPS, now the Mathematical Optimization Society). In 1994, the Dantzig Prize was awarded to Wets and also to the French pioneer in nonsmooth computational-optimization, Claude Lemaréchal. Wets's contributions included developing set-valued analysis, including metric spaces of sets, which he used to study the convergence of epigraphs; Wets's ideas of epigraphical convergence was used to study the convergence iterative methods of stochastic optimization and has had applications in the approximation theory of statistics. A metric theory of finite-dimensional epigraphical convergence ("cosmic convergence") appears in Variational analysis. Wets and his coauthor R. Tyrrell Rockafellar were awarded the 1997 Frederick W. Lanchester Prize by the Institute for Operations Research and the Management Sciences (INFORMS) for their monograph Variational Analysis, which was published in November 1997 and copyrighted in 1998. With Rockafellar, Wets proposed, studied, and implemented the progressive-hedging algorithm for stochastic programming. Besides his theoretical and computational contributions, Wets has worked with applications on lake ecology (IIASA), finance (Frank Russel investment system), and developmental economics (World Bank). He also consulted with the development of professional stochastic-optimization software (IBM). Wets died on 1 April, 2025, at the age of 88.

See also Pompeiu–Hausdorff distance

References

Sources Aardal, Karen (July 1995). "Optima interview Roger J.-B. (sic.) Wets" (PDF). Optima: Mathematical Programming Society Newsletter. 46. Mathematical Programming Society: 3–5. Anonymous, COSP (1 November 2004). Roger J-B Wets (PDF). Pioneers in Stochastic Programming. Committee on Stochastic Programming (COSP). Archived from the original (PDF) on 3 March 2012. Retrieved 12 March 2012. Anonymous, INFORMS (1998). "Roger J-B Wets, Past awards: 1977 Frederick W. Lanchester Prize: Winner". Institute for Operations Research and the Management Sciences (INFORMS). Archived from the original on 24 May 2012. Retrieved 12 March 2012. Rockafellar, R. Tyrrell; Wets, Roger J-B (2005) [1996]. Variational Analysis (PDF). Grundlehren der mathematischen Wissenschaften (Fundamental Principles of Mathematical Sciences). Vol. 317 (third corrected printing ed.). Berlin: Springer-Verlag. pp. xiv+733. doi:10.1007/978-3-642-02431-3. ISBN 978-3-540-62772-2. MR 1491362. Retrieved 12 March 2012. Vicente, L .N. (2004). "An Interview with R. Tyrrell Rockafellar" (PDF). SIAG/Opt News and Views. 15 (1). Society for Industrial and Applied Mathematics (SIAM), Special Interest Group in Optimization: 9–14. Retrieved 12 March 2012. Dantzig Prize Committee (1994). "Citation of Roger Wets (for the George Dantzig Prize, 1994)" (PDF). Optima: Mathematical Programming Society Newsletter. 44. Mathematical Programming Society: 5. Retrieved 12 March 2012. Wets, Roger J-B (31 December 2011). "ROGER J-B WETS (Curriculum Vitae)" (PDF). Department of Mathematics, University of California, Davis. Retrieved 12 March 2012. Wets, Roger J-B (31 December 2011b). "ROGER J-B WETS : Biography-Summary" (PDF). Department of Mathematics, University of California, Davis. Retrieved 12 March 2012.

External links Homepage of Roger J-B Wets at the Mathematics Department of the University of California, Davis. Contains biography, research overviews, lectures and presentations.

Illustrations

Worked examples

Example 1 — a first encounter with Roger J-B Wets

Start with the simplest possible case. Write down what Roger J-B Wets claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Roger J-B Wets before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Roger J-B Wets ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Roger J-B Wets

In research: Roger J-B Wets appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Roger J-B Wets in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Roger J-B Wets is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1937 births, 2025 deaths, 20th-century Belgian mathematicians, so understanding it makes those chapters shorter.
In everyday life: Look for Roger J-B Wets outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Roger J-B Wets in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Roger J-B Wets means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Roger J-B Wets out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Roger J-B Wets in simple terms?

Why does Roger J-B Wets matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Roger J-B Wets?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Roger J-B Wets.