27/2-3/3 (horários e lugar à confirmar)
Palestrante: Manuel Stadlbauer (IM-UFRJ)
Day 1 (27/2 as 11h30) : The Martin boundary - Definition & examples
During the first session, I will discuss the construction principle of the so called Martin boundary, give examples and first applications. References [W], [S], [BS],
Day 2 (28/2 as 11h30): Hyperbolic groups and Ancona's inequality
In this part, I will present the basic properties of Gromov hyperbolic spaces and discuss, how these geometric features affect the potential theoretic Martin boundary. References [A], [BS]
Day 3 (2/3 as 11h30): Analytic tools and a local limit theorem
By adding a parameter to the construction, one may consider the partial derivatives of the building blocks of the Martin boundary. In case of an underlying Gromov hyperbolic space, the geometry then leads to a differential equation which gives access to the precise asymptotics of the iterates of the associated Markov operator. If there is time, I will discuss possible applications to the multiplicative ergodic theorem of Karlsson and Margulis. References [KM], [GL], [G], [BS]
References
[A] Ancona, Negatively curved manifolds, elliptic operators, and the Martin boundary. 1987. [BS] Bispo, Stadlbauer, The Martin boundary of an extension by a hyperbolic group. To appear in Israel Journal of Mathematics. arXiv 2005.03723 [G] Gouezel, Local limit theorem for symmetric random walks in Gromov-hyperbolic groups. 2014. [GL] Gouezel, Lalley, Random walks on co-compact Fuchsian groups. 2013. [KM] Karlsson, Margulis, A multiplicative ergodic theorem and nonpositively curved spaces. 1999. [W] Woess, Denumerable Markov chains - EMS Textbooks in Mathematics. 2009. [S] Schwartz, Thermodynamic Formalism for Transient Potential Functions. 2019.
Seminários de tópicos satélites
27/2 as 9h00: Operador de Ruelle: Gabriel L. & Juan M.
28/2 as 9h00: Espaços métricas hiperholicos au gromov: Eric B., Fabián L.
1/3 as 9h00: O bordo de um espaço hiperbolico: Manuel S., Matheus del Valle
1/3 as 11h30: Teorema de Karlsson-Margulis: Heric C. & Lamartine M.
2/3 as 9h00: A fronteira de martin: Manuel S.
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