ABSTRACT
How to get the best estimate of eigenvalues for Laplace operator with Dirichlet or Neumann boundary value conditions is a classic and difficult problem. Many authors have contributed their ideas to this problem. Especially, for problem () { − Δ u = λ u i n Ω , u | ∂ Ω = 0 , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003067498/6ba0c26b-f086-40cc-86ed-1693dc596221/content/eq249.tif"/>
