Remarks on extreme eigenvalues of Toeplitz matrices.
Let be a nonempty closed convex subset of a Banach space and a -Lipschitzian rotative mapping, i.eṡuch that and for some real , and an integer . The paper concerns the existence of a fixed point of in -uniformly convex Banach spaces, depending on , and .
We present some consequences of a deep result of J. Lindenstrauss and D. Preiss on -almost everywhere Fréchet differentiability of Lipschitz functions on (and similar Banach spaces). For example, in these spaces, every continuous real function is Fréchet differentiable at -almost every at which it is Gâteaux differentiable. Another interesting consequences say that both cone-monotone functions and continuous quasiconvex functions on these spaces are -almost everywhere Fréchet differentiable....
We investigate rich subspaces of L₁ and deduce an interpolation property of Sidon sets. We also present examples of rich separable subspaces of nonseparable Banach spaces and we study the Daugavet property of tensor products.