Periodička homogenizacija za procese Levyjevog tipa

Autor: Valentić, Ivana
Přispěvatelé: Sandrić, Nikola
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Popis: The main goal of this thesis is to discuss periodic homogenization of a Lévy-type pseudodifferential operator. Our approach to this problem is based on probabilistic techniques. More precisely, as the main result we show that the appropriately centered and scaled Lévy-type process (LTP) generated by this operator converges weakly to a Brownian motion with covariance matrix given in terms of the operator coefficients. We specially focus on a class of Lévy-type processes admitting “small jumps” only and a class of diffusion processes having degenerate diffusion term. These results generalize and refine the classical and well-known results related to periodic homogenization of diffusion process and of Lévy-type process in balanced form. In order to resolve these problems, it is necessary to combine both probabilistic and analytical approaches and tools, such as theory of semimartingales, stochastic stability theory and theory of integro-differential equations. Glavni cilj ove disertacije je diskutirati periodičku homogenizaciju pseudo-diferencijalnog operatora Lévyjevog tipa. Naš pristup ovom problemu bazira se na vjerojatnosnim metodama. Preciznije, kao glavni rezultat dokazujemo da odgovarajuće centriran i skaliran proces Lévyjevog tipa generiran takvim operatorom slabo konvergira prema Brownovom gibanju s kovarijacijskom matricom danom u terminima koeficijenata operatora. Posebno se koncentriramo na klasu procesa Lévyjevog tipa koji dozvoljavaju samo “male skokove” i na klasu procesa difuzija s degeneriranim difuzijskim koeficijentom. Ti rezultati generaliziraju i produbljuju klasične i dobro poznate rezultate vezane uz periodičku homogenizaciju difuzije i procesa Lévyjevog tipa u balansiranom obliku. Kako bismo razriješili ove probleme nužno je kombinirati vjerojatnosni i analitički pristup i metode, kao što su teorija semimartingala, teorija stohastičke stabilnosti i teorija integro-diferencijalnih jednadžbi.
Databáze: OpenAIRE