Lower Bounds for the Fundamental Free Membrane Eigenvalue
J. Ladevéze, Pierre Ladevèze · SIAM Journal on Mathematical Analysis · 1979
New lower bounds for the fundamental eigenvalue in the free membrane problem are derived in terms of elementary characteristics of the domain. In the first part, the case of strongly starshaped domains will be dealt with. The second part will introduce a method of estimate for domains which are unions of strongly sharshaped domains.