Polar factorization and pseudo-rearrangements: applications to Pólya–Szegö type inequalities

Autor: Roberta Volpicelli, Adele Ferone
Přispěvatelé: A., Ferone, Volpicelli, Roberta, Ferone, Adele, Volpicelli, R.
Rok vydání: 2003
Předmět:
Zdroj: Nonlinear Analysis: Theory, Methods & Applications. 53:929-949
ISSN: 0362-546X
Popis: We are interested in the polar factorization of a function f defined in an open bounded set Ω⊆ R N . It is well known that there exists a measure preserving map σ such that f=f ∗ ∘σ where f ∗ is the decreasing rearrangement of f . We prove that, under suitable assumptions, besides the classical polar factorization of f we have f= f u ∘σ where f u is a pseudo-rearrangement of f with respect to the measurable function u and σ is the measure preserving map such that u=u ∗ ∘σ . As an application, we characterize those functions that realize equality in the Polya–Szego inequality.
Databáze: OpenAIRE