Information om seminarier och ho¨gre undervisning i matematiska¨ amnen i Stockholmsomra±det NR 33 FREDAGEN DEN 12 OKTOBER 2001 ± BRAKET SEMINARIER Veckobladet fra± n Fr 10–12 kl. 15.15. Popula¨ra kollokviet. Peter Jones, Institutionen fo¨r matematik Yale University och Institut Mittag--Leffler: Multi- vid Kungl Tekniska Ho¨gskolan scale analysis, the travelling salesman, and geo- och Matematiska institutionen metry of measures. Seminarierum 3721, Institu-- vid Stockholms universitet tionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se Bra± ket nr 32 sidan 4. Redakto¨r: Gunnar Karlsson Ma± 10–15 kl. 13.15 – 14.15. Potential Analysis Seminar. Telefon: 08--790 84 79 Anders Szepessy: When is adaptive approxima- Adress fo¨r e-post: tion good? Seminarierum 3733, Institutionen fo¨r [email protected] matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se sidan 4. Bra˚ket pa˚Internet: http://www. ± math.kth.se/braaket.html eller Ma 10–15 kl. 13.15 – 15.00. Algebraseminarium — licen- http://www.math.kth.se/braket/ tiatseminarium i matematik. Jesper Carl- stro¨m presenterar sin licentiatavhandling: Wheels Postadress: — On Division by Zero. Diskutant: Karl Meinke, ± Red. fo¨r Braket Nada, KTH. Rum 306, hus 6, Matematiska insti-- Institutionen fo¨r matematik tutionen, SU, Kra¨ftriket. Se sidan 4. KTH ± Ma 10–15 kl. 15.15 – 16.00. Seminarium i finansiell 100 44 Stockholm matematik. Michael Hemph presenterar sitt ------- examensarbete: Bond Trading Strategies Based on Term Structure Models. Seminarierum 3733, Insti-- Sista manustid fo¨r na¨sta nummer: tutionen fo¨r matematik, KTH, Lindstedtsva¨gen Torsdagen den 18 oktober ± kl. 13.00. 25, plan 7. Se Braket nr 32 sidan 4. Ma± 10–15 kl. 16.15 – 17.00. Seminarium i finansiell matematik. Nikolas Santikos presenterar sitt Rolf Schock Prizes 2001 examensarbete: Pricing Spread options on Swaps. Seminarierum 3733, Institutionen fo¨r matematik, Professor emeritus Saul A. Kripke ± har fa± tt priset i logik och filosofi. KTH, Lindstedtsva¨gen 25, plan 7. Se Braket nr 32 Professor Elliott H. Lieb har fa± tt sidan 6. priset i matematik. I samband med Ti 10–16 kl. 10.15. Plurikomplexa seminariet. Robert priserna¨ ager ett symposium rum Berman, Go¨teborg: From the Yamabe problem on tisdagen den 23 oktober och ges a Riemann surface to Seiberg-Witten invariants. fo¨rela¨sningar onsdagen den 24 Rum 306, hus 6, Matematiska institutionen, SU, oktober pa± Kungl. Vetenskaps-- Kra¨ftriket. Se sidan 3. akademien. Se sidan 7. Fortsa¨ttning pa± na¨sta sida. 2 Seminarier (fortsa¨ttning) Ti 10–16 kl. 11.00 – 12.00. Optimization and Systems Theory Seminar. (Observera dagen!) Natalia Balashevich, Department of Control Processes Theory, Insti-- tute of Mathematics, National Academy of Sciences of Belarus, Minsk: Real-time optimization of control systems. Seminarierum 3721, Institutionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se sidan 5. Ti 10–16 kl. 13.15 – 15.00. Seminarium anordnat av Centrum fo¨r sa¨kerhetsforsk- ± ning, KTH. Professor Ake Svensson, Matematisk statistik, SU, och epidemio-- logiska enheten, Smittskyddsinstitutet: Sensitivitet, specifitet och positivt predik- tionsva¨rde. Sal V2, KTH, Teknikringen 76, 2 tr. Se sidan 6. Ti 10–16 kl. 14.00. Plurikomplexa seminariet. Mikael Passare, SU: Complex convex- ity — recent results of Kiselman and Ho¨rmander. Rum 306, hus 6, Matematiska institutionen, SU, Kra¨ftriket. Se sidan 4. Ti 10–16 kl. 14.30 – 15.30. Mittag-Leffler Seminar. Lukas Geyer, Dortmund: Linear- ization, Siegel disks, and Brjuno numbers. Institut Mittag--Leffler, Aurava¨gen 17, Djursholm. Ti 10–16 kl. 16.00 – 17.00. Mittag-Leffler Seminar. Peter Jones, New Haven: An introduction to harmonic measure and scaling: Part I. Institut Mittag--Leffler, Aurava¨gen 17, Djursholm. On 10–17 kl. 10.15 – 12.00. Kombinatorikseminarium. Faina I. Solov’eva, Novosibirsk: On components of perfect binary codes. Seminarierum 3733, Institutionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se sidan 6. On 10–17 kl. 13.15 – 14.15. Seminarium i analys och dynamiska system. Krzysztof Burdzy, University of Washington, Seattle, och Institut Mittag--Leffler: The heat equation and reflected Brownian motion in domains with moving boundaries. Seminarierum 3721, Institutionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se sidan 8. On 10–17 kl. 15.15. Seminarium i matematisk statistik. Rolf Sundberg, SU: Statistics in chemistry — chemometrics. Rum 306, Cram´errummet, hus 6, Matematiska institutionen, SU, Kra¨ftriket. Se sidan 8. On 10–17 kl. 15.15 – 17.00. Seminarium om beslutssto¨d och informationsfusion i ledningssystem. (Observera dagen!) Dr Alexander E. R. Woodcock: Mathe- matical models of combat. Sal E2, KTH, Lindstedtsva¨gen 3, b.v. Se sidan 5. To 10–18 kl. 14.00 – 15.00. Mittag-Leffler Seminar. Harry Kesten, Ithaca: An intro- duction to percolation: Part II. Institut Mittag--Leffler, Aurava¨gen 17, Djursholm. To 10–18 kl. 15.30 – 16.30. Mittag-Leffler Seminar. Speaker to be announced: Title to be announced. Institut Mittag--Leffler, Aurava¨gen 17, Djursholm. To 10–18 kl. 16.15 – 18.00. Seminarium i matematik och fysik vid Ma¨lardalens ho¨g- skola (Eskilstuna). PRIM-gruppen, La¨rarho¨gskolan i Stockholm: Analys och bedo¨mning av elevers kunskaper i matematik. Lektionssal A309, Ma¨lardalens ho¨g-- skola, Eskilstuna. Ma± 10–22 kl. 11.15. Seminarium. Enrico Bombieri, IAS, Princeton: Title to be announced (a topic in intersection theory). Seminariet¨ ager rum pa± KTH. Lokal meddelas i na¨sta nummer av Bra± ket. Fortsa¨ttning pa± na¨sta sida. 3 Seminarier (fortsa¨ttning) Ma± 10–22 kl. 13.15 – 14.15. Potential Analysis Seminar. Nina Uraltseva: Contact between free and fix boundary in a parabolic variational inequality. Seminarierum 3733, Institutionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Ma± 10–22 kl. 13.15 – 15.00. Algebra and Geometry Seminar. Valentina Barucci, Universit`adi Roma 1: On an equivalence relation between algebroid curves. Rum 306, hus 6, Matematiska institutionen, SU, Kra¨ftriket. Se sidan 6. Ma± 10–22 kl. 15.15 – 17.00. Seminarium i matematisk statistik. Torkel Erhardsson: Strong memoryless times and rare events in stationary Markov renewal processes. Seminarierum 3733, Institutionen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. Se sidan 9. Ti 10–23 kl. 15.15 – 17.00. Seminarium om beslutssto¨d och informationsfusion i ledningssystem. Mats Persson, Fo¨rsvarsho¨gskolan, och Klas Wallenius, Nada, KTH, och SaabTech Systems AB: Enskild och gemensam situationsuppfatt- ning. Sal E32, KTH, Lindstedtsva¨gen 3, b.v. Se sidan 8. On 10–24 kl. 15.15. Seminarium i matematisk statistik. Nader Tajvidi, Lunds tek-- niska ho¨gskola: Parametric and nonparametric analysis of temporal trend in extreme values with applications to wind storm losses and temperature data. Rum 306, Cram´errummet, hus 6, Matematiska institutionen, SU, Kra¨ftriket. Se sidan 9. On 10–24 kl. 15.15 – 16.00. Seminarium i matematik och fysik vid Ma¨lardalens ho¨g- skola (Va¨stera± s). Christos Papahristodoulou, Ma¨lardalens ho¨gskola: Optimal portfolios. Lektionssal N24, Ma¨lardalens ho¨gskola, Va¨stera± s. PLURIKOMPLEXA SEMINARIET Robert Berman: From the Yamabe problem on a Riemann surface to Seiberg--Witten invariants Abstract: The classical Yamabe problem, on a Riemann surface, concerns the problem of conformally deforming a given metric to one of constant curvature. To be concrete, on could try to deform an egg to a sphere. Analytically, the problem amounts to solving a certain quasi--linear PDE. I will show how a naı¨ve attempt to use the classical continuity method in PDE--theory fails, and we are led to a “change of variables”. In this way we obtain a reformulation of the problem in terms of holomorphic geometry. Namely, the problem of deforming the standard @--operator to a “special” one. Now the continuity method can be successfully applied. In fact, the new equations turn out to be the Seiberg--Witten equations over a Riemann surface. In 1994 these equations, coming from physics, revolutionized (real) four--dimensional differential topology, and they have also been successfully applied to certain problems in complex analysis. Relating the Seiberg--Witten equations in the simpler setting of two (real) dimensions to the classical Yamabe problem provides a certain intuition for the four--dimen-- sional situation, since many features are shared. Also it leads to, yet another, solution of the Yamabe problem (in this special case: we will only consider the negative curvature case on a Riemann surface). Tid och plats: Tisdagen den 16 oktober kl. 10.15 i rum 306, hus 6, Matematiska institutio-- nen, SU, Kra¨ftriket. 4 POTENTIAL ANALYSIS SEMINAR Anders Szepessy: When is adaptive approximation good? Abstract: In the 1960’s Bakhvalov and Smolyak proved that, using a fixed number of function evaluations to approximate a given linear functional, there is a non--adaptive (linear) approximation which has as small maximal error as any adaptive (non--linear) method, with functions in a convex symmetric subset of a function space. Starting from Bakhvalov’s and Smolyak’s result, I will discuss adaptive approximation and give ODE, SDE and PDE examples where adaptive methods indeed are better. Tid och plats: Ma± ndagen den 15 oktober kl. 13.15 – 14.15 i seminarierum 3733, Institutio-- nen fo¨r matematik, KTH, Lindstedtsva¨gen 25, plan 7. ALGEBRASEMINARIUM — LICENTIATSEMINARIUM I MATEMATIK Jesper Carlstro¨m presenterar sin licentiatavhandling: Wheels — On Division by Zero Diskutant: Karl Meinke, Nada, KTH. Abstract: We show how to extend any commutative ring (or semiring) so that division by any element, including 0, is in a sense possible. The resulting structure is what is called a wheel. Wheels are similar to rings, but 0x = 0 does not hold in general; the subset fx j 0x = 0g of any wheel is a commutative ring (or semiring), and any commutative ring (or semiring) with identity can be described as such a subset of a wheel.