Displaying similar documents to “Integer sets having the maximum number of distinct differences.”

Bounds for the first Dirichlet eigenvalue of triangles and quadrilaterals

Pedro Freitas, Batłomiej Siudeja (2010)

ESAIM: Control, Optimisation and Calculus of Variations

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We prove some new upper and lower bounds for the first Dirichlet eigenvalue of triangles and quadrilaterals. In particular, we improve Pólya and Szegö's [  (1951)] lower bound for quadrilaterals and extend Hersch's [  (1966) 457–460] upper bound for parallelograms to general quadrilaterals.