A Counterexample Regarding a Two-phase Problem for Harmonic Measure in VMO

Let Ω+⊂Rn+1 be a vanishing Reifenberg flat domain such that Ω+ and Ω- = Rn+1\Ω+¯ have joint big pieces of chord-arc subdomains and such that the outer unit normal to ∂Ω+ belongs to VMO(ω+), where ω± is the harmonic measure in Ω±. Up to now it was an open question if these conditions imply that logdω...

Descripción completa

Detalles Bibliográficos
Autor: Tolsa Domènech, Xavier|||0000-0001-7976-5433
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:311855
Acceso en línea:https://ddd.uab.cat/record/311855
https://dx.doi.org/urn:doi:10.1007/s11118-025-10214-3
Access Level:acceso abierto
Palabra clave:Harmonic measure
Two-phase problem
Reifenberg flat domains
Descripción
Sumario:Let Ω+⊂Rn+1 be a vanishing Reifenberg flat domain such that Ω+ and Ω- = Rn+1\Ω+¯ have joint big pieces of chord-arc subdomains and such that the outer unit normal to ∂Ω+ belongs to VMO(ω+), where ω± is the harmonic measure in Ω±. Up to now it was an open question if these conditions imply that logdω-dω+∈VMO(ω+). In this paper we answer this question in the negative by constructing an appropriate counterexample in R2, with the additional property that the outer unit normal to ∂Ω+ is constant ω+-a.e. in ∂Ω+.