PDE実解析研究会

過去の記録 ~04/19次回の予定今後の予定 04/20~

開催情報 火曜日 10:30~11:30 数理科学研究科棟(駒場) 056号室
担当者 儀我美一、石毛和弘、三竹大寿、米田剛
セミナーURL http://coe.math.sci.hokudai.ac.jp/sympo/pde_ra/
目的 首都圏の偏微分方程式、実解析の研究をさらに活発にするために本研究会を東大で開催いたします。
偏微分方程式研究者と実解析研究者の討論がより日常的になることを目指しています。
そのため、講演がその分野の概観をもわかるような形になるよう配慮いたします。
また講演者との1対1の討論がしやすいように講演は火曜の午前とし、午後に討論用の場所を用意いたします。
この研究会を通して皆様に気楽に東大を訪問していただければ幸いです。
北海道大学のHPには、第1回(2004年9月29日)~第38回(2008年10月15日)の情報が掲載されております。

2005年03月02日(水)

10:30-11:30   数理科学研究科棟(駒場) 270号室
Italo Capuzzo-Dolcetta 氏 (Universita di Roma) 10:30-11:30
The maximum principle in unbounded domains
[ 講演概要 ]
The issue of the talk is the validity of the Weak Maximum Principle for functions u satisfying a second-order partial differential inequality of the form
(*) F(x,u,Du,D^2u) ≧ 0
in a domain A of the n-dimensional euclidean space.
The main result presented in the lecture is that for bounded above upper semicontinuous functions verifying
(*) in the viscosity sense, the inequality u≦ 0 on the boundary ∂A is propagated in the interior of the domain itself, under suitable conditions on F and A.
These conditions include ellipticity of F, a general geometric condition on the (possibly) unbounded domain A and a joint requirement involving the spread of A and the decay of first order terms at infinity.
This result, contained in I.C.D, A.Leoni, A.Vitolo "The Alexandrov-Bakelman-Pucci weak Maximum Principle for fully nonlinear equations in unbounded domains", to appear in Comm.in PDE's, extends previous results due to X.Cabré and L.Caffarelli-X.Cabré.
In the second part of the talk we present different versions of Weak Maximum Principle, namely for solutions growing exponentially fast of (*) in narrow domains and for solutions of
(**) F(x,u,Du,D^2u) + c(x)u ≧ 0
(c changing sign) in domains of small measure.
[ 参考URL ]
http://coe.math.sci.hokudai.ac.jp/sympo/pde_ra/index.html
Antonio Siconolfi 氏 (Universita di Roma) 11:45-12:45
Aubry set and applications
[ 講演概要 ]
For given Hamiltonian H(x, p) continuous and quasiconvex in the second argument, defined in Rn × Rn or on the cotangent bundle of a compact boundaryless manifold, we consider the equation

H= c

with c critical value, i.e. for which the equation admits locally Lipschitzcontinuous a.e. subsolutions, but not strict subsolutions. We show that there is a subset of the state variable space, called Aubry set and denoted by A, where the obstruction to the existence of such subsolutions is concentrated. We give a metric characterization of A, and we discuss its main properties.

They are applied to a projection problem in a Banach space, to the study of the largetime behaviour of subsolutions to a timedependent HamiltonJacobi equation, and to construct a Lyapunov function for a perturbed dynamics, under suitable stability assumptions.
[ 参考URL ]
http://coe.math.sci.hokudai.ac.jp/sympo/pde_ra/index.html