Jan Lang

Review of recent developments in approximation theory for Hardy-type operators and Sobolev embeddings (description of the exact values of s-numbers and widths) A special chapter devoted to the theory of generalized trigonometric functions (presented for the first time in a book) Description of connections between optimal approximations, eigenvalues for the p-Laplacian and generalized trigonometric functions Includes supplementary material: sn.pub/extras