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Seminar "Bogoljub Stanković" (since 1962)

Chair: Academician Stevan Pilipović

SS 2018-2019: Monday, 12.15, DMI room 60

20.01.2020. Federico Bastianoni, University of Turin, Italia
Decay and smoothness for eigenfunctions of localization operators
Sažetak
In this talk we present localization operators Aa φ1,φ2 in the framework of time-frequency analysis. After an historical introduction, we represent Aa φ1,φ2 as a Weyl operator and show modulation spaces which appear to be the appropriate class for symbols a. Some results about decay and smoothness for L2 -eigenfunctions of localization operators from [1], an article by E. Cordero, F. Nicola and myself, are shown. Eventually, we exhibit an expected generalization in the setting of Gelfand-Shilov spaces. This will consist of a research topic in collab- oration with N. Teofanov.
Reference
[1] F. Bastianoni, E. Cordero and F. Nicola. Decay and Smoothness for Eigenfunctions of Localization Operators. Submitted. ArXiv:1902.03413v2
13.01.2020. Tijana Šukilović, Matematički fakultet, Beograd
Geodezijski ekvivalentne metrike na homogenim prostorima
Sažetak
Dve metrike na mnogostrukosti su projektivno ili geodezijski ekvivalentne ako se skupovi njihovih neparametrizovanih geodezijskih krivih poklapaju. Na ovom predavanju biće razmatrane G-invarijantne metrike proizvoljne signature na homogenom prostoru G/H. Biće pokazano da geodezijski ekvivalentne G-invarijantne metrike na G/H moraju imati istu Levi-Čivita povezanost, odnosno moraju biti afino ekvivalentne. Takođe, posebna pažnja će biti posvećena vezi između geodezijske ekvivalentnosti i grupa holonomija. Specijalno, za slučaj Lijevih grupa, biće prikazan algoritam kojim se za datu levo-invarijantnu metriku konstruišu sve njoj geodezijski ekvivalentne metrike.
23. 12. 2019. Filip Tomić, University of Novi Sad
Skoro analitička proširenja i talasni front
Sažetak
U radu [1] je dokazan rezultat o reprezentaciji ultradistribucija kao graničnih vrednosti analitičkih funkcija. U dokazu se koriste skoro analitička proširenja ultradiferencijabilnih funkcija kao njihovih test prostora. Takva proširenja su nedavno analizirana i u radu [4]. Jedna od primena ovakvih rezultata je u analizi talasnog fronta kompozicije ultradistribu- cija sa analitičkim funkcijama (pullback, videti [2]). U okviru predavanja će biti dat prikaz postojećih rezultata vezanih za granične vrednosti analitičkih funkcija u prostorima ultradistribucija. Takodje će biti prikazani i rezultati u okviru uopštenih funkcija Ževrea.
Reference
[1] Pilipović, Stevan Structural theorems for ultradistributions Different aspects of differentiability (Warsaw, 1993). Dissertationes Math. (Rozprawy Mat.) 340 (1995), 223–235.
[2] Pilipović, Stevan Microlocal properties of ultradistributions. Composition and kernel type operators. 50th anniversary of the Mathematical Institute, Serbian Academy of Sciences and Arts (Belgrade, 1996). Publ. Inst. Math. (Beograd) (N.S.) 64(78) (1998), 85–97.
[3] R. Carmichael, A. Kaminski, S. Pilipović, Notes on Boundary Values in Ultradistribution Spaces, Lecture Notes Series of Seul University, 49, 1999.
[4] Fürdös, Stefan; Nenning, David Nicolas; Rainer, Armin; Schindl, Gerhard Almost analytic extensions of ultradifferentiable functions with applications to microlocal analysis. J. Math. Anal. Appl. 481 (2020), no. 1, 123451, 51 pp.
[5] H. Komatsu, Ultradistributions, I: Structure theorems and a characterization. J. Fac. Sci. Univ. Tokyo, Sect. IA Math., 20 1 (1973), 25–105.
[6] Lars Hörmander, The Analysis of Linear Partial Differential Operators I, Springer, 1990.
[7] Pilipović, Stevan, Teofanov, Nenad, Tomić, Filip, Boundary values in extended Gevrey ultradistributions, in preperation.
12.12. 2019.
(četvrtak)
Vesa Vuojamo, Aalto University, Finland
Euclidean time-frequency Transforms
Sažetak
We will present some new Euclidean space results on characterizing properties of the Cohen class time-frequency transformsand the corresponding pseudo-differential quantization.
09. 12. 2019. Miloš Kurilić, University of Novi Sad, Serbia
Koliko modela ima teorija?
Sažetak
Sa I(T) označavamo (kardinalni) broj neizomorfnih prebrojivih modela prebrojive kompletne teorije prvog reda T. Ovaj broj je manji ili jednak kontinuumu (c), a klasični primeri Cantora, Ehrenfeuchta i Vaughta pokazuju da I(T) može da bude bilo koji prirodan broj sem 2, te da postoje teorije sa prebrojivo mnogo kao i teorije sa kontinuum mnogo modela. 1959. godine (objavljeno 1961.) Robert Vaught je postavio pitanje koje se svodi na pretpostavku da, ako je I(T) neprebrojiv kardinalni broj, onda je I(T) = c (Vaught’s conjecture).
Kao što je Cantorov problem kontinuuma(CH, razrešen u radovima Godela (1943) i Cohena (1963)) bio prvi na Hilbertovoj listi otvorenih problema za 20. vek (1900), Vaughtova hipoteza,tj. “problem kontinuuma za modele” je prvi na listi otvorenih problema teorije modela (Wikipedia).
Do sada, Vaughtova hipoteza je potvrđena za neke klase struktura (tj. njihovih teorija). Npr. za linearna uređenja (Rubin, 1974), drveta (Steel, 1978), omega-stabilne teorije (Shelah, Harrington, Makkai, 1984), o-minimalne teorije (Mayer, 1988). Na predavanju će biti dato više detalja i primera koji se tiču ovog problema; biće prikazani i neki novi rezultati
02. 12. 2019. Nikola Sarajlija, University of Novi Sad, Serbia
Primena min-max principa u PDJ
04. 11. 2019. Nenad Teofanov, University of Novi Sad, Serbia
Multipliers: From the Fourier multipliers to continuous frames
21. 10. 2019. Scientific organization and project activities
14. 10. 2019. Jelena Aleksić, Univeristy of Novi Sad, Serbia
Two scale defect measures
07. 10. 2019. Lenny Neyt, Ghent University, Belgium
Contributions to the generalised asymptotics of ultradistributions
09. 04. 2019. Danka Lučić, University of Jyväskylä, Finland
Weakly differentiable functions on metric measure spaces and the notion of infinitezimal Hilbertianity
09. 04. 2019. Enrico Pasqualetto, University of Jyväskylä, Finland
Universal infinitesimal Hilberianity of sub-Riemannian manifolds
18. 03. 2019. Vladimir Kapustin, V. A. Stelkov Mathematical Institute, St.Petesburg, Russia
Beurling's theorem, Davenport's formula, and the Riemann Hypothesis
17. 12. 2018. Endre Süli, Oxford University, Great Britain
Analysis and approximation of Hamilton–Jacobi–Bellman equations with Cordes coefficients
10. 12. 2018. Nenad Morača
Varijacije reverzibilnosti
03. 12. 2018.
Dogovor o rasporedu predavanja
26. 11. 2018. Nevena Mićić
Otkazano
19. 11. 2018. Božidar Jovanović, MI SANU, Beograd
Uopštenje Jakobi-Mamfordovih sistema i afini primovi verijeteti

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Seminar for Numerical Mathematics

Chair: Prof. Dr Nataša Krejić

SS 2018-2019: Friday, 13.15, DMI PhD room -- the first floor in the new part

27. 05. 2019. Ljiljana Teofanov
SDFEM on a Duran-type mesh for a convection-diffusion problem
20. 05. 2019. Tijana Stojančević
On an inexact restoration subgradient method
13. 05. 2019. Goran Radojev
A posteriori error estimations for parabolic problems
06. 05. 2019. Nataša Krklec Jerinkić
Distributed methods for system of linear equations
22. 04. 2019. Davor Kumozec
Numerical solution to transport equation by method of characteristics
25. 03. 2019. Zoltan Pap
Projection based CG methods for solving  systems of large-scale nonlinear monotone equations
18. 03. 2019. Zoranka Desnica
Robust optimization
11. 01. 2019. Dušan Jakovetić
TBA
21. 12. 2018. Bojana Anđelković Ćirković
Optimization Techniques Applied on Problem of Explaining Individual Classifications
14. 12. 2018. Tijana Stojančević
Subgradient Optimization Methods
07. 12. 2018. Katarina Vla Panić
Reduction Method with Biased Gradient Approximation
23. 11. 2018. Greta Malaspina
Methods for Finite Sum Optimization
21. 11. 2018. Stephan Schluter
Time Series Outliers Detection via Wavelets
16. 11. 2018. Nataša Krejić
Inexact Restoration - Trust Region Approach
09. 11. 2018. Stevan Armacki
Distributed Trust Region Methods

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