- Maximal regularity of elliptic operators
- Sectorial operators and their regularity properties
- Semigroup theory
- Functional calculi
- Harmonic analysis on Banach spaces
Dr. Stephan Fackler
- 2006-2011: Study of Mathematics with minor in Physics at Îçҹ̽»¨
- 2011-2014: PhD in Mathematics (supervisor: Wolfgang Arendt)
- 2015-2017: postdoctoral researcher for the project (regularity of evolutionary problems via harmonic analysis and operator theory) financed by the German Research Foundation (DFG, Deutsche Forschungsgemeinschaft)
Teaching
Lecture notes of previous courses:
- Lecture Notes Mathematical Foundations of Quantum Mechanics (not proofread)
- Summer term 15: Lecturer for Mathematical Foundations of Quantum Mechanics
- Winter term 14/15: Exercises in Measure Theory
- Winter term 14/15: Student seminar Real and Complex Analysis
- Winter term 14/15: Local coordinator for the Internet Seminar on Evolution Equations
- Winter term 13/14: Exercises in Dynamical Systems
- Winter term 13/14: Reading Course Harmonic Analysis
- Summer term 13: Exercises in Introduction to Ordinary Differential Equations
- Summer term 13: Exercises in Introduction to Complex Analysis
- Winter term 12/13: Exercises in Functional Analysis (Temporary)
- Summer term 12: Student seminar Ergodic Theory
- Summer term 12: Exercises in Introduction to Functional Analysis
- Winter term 11/12: Student seminar Harmonic Analysis
- Summer term 11: Teaching Assistant for Analysis II
- Winter term 10/11: Student Teaching Assistant for HM III für Physiker
- Summer term 10: Student Teaching Assistant for Introduction to Functional Analysis
- Winter term 09/10: Exercises in Calculus of Variations
- Summer term 09: Student Teaching Assistant for HM I für Physiker
Research
During my time as a doctoral and postdoctoral studies my research was focused on the maximal L^p-regularity of abstract Cauchy problems and related issues, such as the holomorphic functional calculus for sectorial operators. During my PhD I was mainly interested in structural questions. In particular, I studied the extrapolation problem for maximal regularity. As a postdoc my focus lied on the maximal regularity of non-autonomous elliptic operators. Moreover, I have done some research on harmonic analysis on Banach spaces (operator-valued Fourier multipliers and Calderón-Zygmund operators).
Further, I am interested in the theory of one parameter semigroups (C_0-semigroups) and in the geometry of Banach spaces, particularly in view of possible applications to semigroup theory.
My research profiles: | | |
- J. L. Lions' Problem on Maximal Regularity (with W. Arendt & D. Dier), Arch. Math. (Basel) 109 (2017), no. 1, 59-72 (, )
- Non-Autonomous Maximal $L^p$-Regularity under Fractional Sobolev Regularity in Time, Preprint ()
- Non-Autonomous Maximal Regularity for Forms Given by Elliptic Operators of Bounded Variation, J. Differential Equations 263 (2017), no. 6, 3533–3549 (, )
- J.-L. Lions' Problem Concerning Maximal Regularity of Equations Governed by Non-Autonomous Forms, Ann. Inst. H. Poincaré Anal. Non Linéaire 34 (2017), no. 3, 699–709 (, )
- Non-Autonomous Maximal L^p-Regularity for Rough Divergence Form Elliptic Operators, Preprint ()
- A Short Counterexample to the Inverse Generator Problem on non-Hilbertian Reflexive L^p-spaces, Arch. Math. (Basel) 106 (2016), no. 4, 383–389 (, )
- Isometric dilations and H^{\infty} calculus for bounded analytic semigroups and Ritt operators (with C. Arhancet & C. Le Merdy), Trans. Amer. Math. Soc. 369 (2017), no. 10, 6899–6933 (, )
- Maximal Regularity: Positive Counterexamples on UMD-Banach Lattices and Exact Intervals for the Negative Solution of the Extrapolation Problem, Proc. Amer. Math. Soc. 144 (2016), no. 5, 2015–2028 (, )
- Regularity Properties of Sectorial Operators: Counterexamples and Open Problems, Operator semigroups meet complex analysis, harmonic analysis and mathematical physics, 171–197, Oper. Theory Adv. Appl., 250, Birkhäuser/Springer, Cham, 2015. (, )
- On the structure of semigroups on L_p with a bounded H^{\infty}-calculus, Bull. Lond. Math. Soc. 46 (2014), no. 5, 1063–1076 (, )
- Local Strong Solutions for the Non-Linear Thermoelastic Plate Equation on Rectangular Domains in L^p-Spaces (with T. Nau), NoDEA Nonlinear Differential Equations Appl. 21 (2014), no. 6, 775–794 (, )
- The Kalton-Lancien Theorem Revisited: Maximal Regularity does not extrapolate, J. Funct. Anal. 266 (2014), no. 1, 121–138 (, )
- Regularity of semigroups via the asymptotic behaviour at zero, Semigroup Forum 87 (2013), no. 1, 1–17 (, )
- An explicit counterexample for the L^p-maximal regularity problem, C. R. Math. Acad. Sci. Paris 351 (2013), no. 1–2, 53–56 ()
- (PhD thesis)
- Holomorphic Semigroups and the Geometry of Banach Spaces (Diploma thesis)
- 15 May 2017: Ein neuer Zugang zum Dilatationsresultat von Akcoglu–Sucheston (Forschungsseminar, Ulm)
- 27 April 2017: A new approach to the Akcoglu–Sucheston dilation theorem for positive contractionson L^p-spaces (Emergent trends of Complex Analysis and Functional Analysis, Będlewo)
- 14 February 2017: Non-Autonomous Maximal Regularity of Elliptic Operators in Divergence Form (Seminar in Analysis, TU Delft)
- 16 December 2016: Entropy for Mathematicians (AGFA & IAA Workshop, Blaubeuren)
- 27 May 2016: Operator Theoretic Tools for Harmonic Analysis and PDE (Workshop Singular integrals and partial differential equations, Helsinki)
- 22 April 2016: Non-autonomous maximal regularity (Joint Harmonic Analysis and PDE Seminar of the University of Helsinki and Aalto University)
- 1 February 2016: Bekanntes und Unbekanntes über den ±á°÷∞-°²¹±ô°ìü±ô (Oberseminar Funktionalanalysis und Dynamische Systeme, Universität Kiel)
- 23 November 2015: Banachskalen und nichtautonome Maximale Regularität auf Banachräumen (Forschungsseminar, Ulm)
- 2 October 2014: Structural Properties of Maximal Regularity (Workshop Functional calculus and Harmonic analysis of semigroups, Besançon)
- 5 December 2013: Dilatationen und Funktionalkalkül auf L^p- & UMD-Räumen (Forschungsseminar, Ulm)
- 30 November 2013: Positive Halbgruppen sind generisch für beschränkten ±á°÷∞-°²¹±ô°ìü±ô auf L^p (TULKA workshop „40 Jahre Ergodentheorie, 40 Jahre AGFA“, Tübingen)
- 23 October 2013: On the structure of semigroups on L_p with a bounded H^{\infty}-calculus (Journées du GdR «Analyse Fonctionelle, Harmonique et Probabilités», Lyon)
- 4 September 2013: A stochastic characterization of maximal parabolic L^p-regularity (Workshop Probability, Analysis and Geometry, Ulm)
- 6 June 2013: Maximal Regularity does not extrapolate (Operator Semigroups meet Complex Analysis, Harmonic Analysis and Mathematical Physics, Herrnhut)
- 11 June 2012: Regularity of Semigroups via the Asymptotic Behaviour at Zero (8th Euro-Maghrebian Workshop on Evolution Equations, Lecce)
- 15 May 2012: Regularität von Halbgruppen durch das asymptotische Verhalten in der Null (TULKA, Karlsruhe)
- 31 January 2011: B-konvexe Räume sind K-konvex (Forschungsseminar, Ulm)