Some geometric inequalities for the Holmes-Thompson definitions of volume and surface area in Minkowski spaces.
The Fixed Point Theory for nonexpansive mappings is strongly based upon the geometry of the ambient Banach space. In section 1 we state the role which is played by the multidimensional convexity and smoothness in this theory. In section 2 we study the computation of the normal structure coefficient in finite dimensional lp-spaces and its connection with several classic geometric problems.
We give sufficient conditions implying that the projective tensor product of two Banach spaces and has the -sequentially Right and the --limited properties, .
We construct, by a variation of the method used to construct the Tsirelson spaces, a new family of weak Hilbert spaces which contain copies of l₂ inside every subspace.
Using some known lifting theorems we present three-space property type and permanence results; some of them seem to be new, whereas other are improvements of known facts.
It is shown that under natural assumptions, there exists a linear functional does not have supremum on a closed bounded subset. That is the James Theorem for non-convex bodies. Also, a non-linear version of the Bishop-Phelps Theorem and a geometrical version of the formula of the subdifferential of the sum of two functions are obtained.
We prove that every bounded, uniformly separated sequence in a normed space contains a “uniformly independent” subsequence (see definition); the constants involved do not depend on the sequence or the space. The finite version of this result is true for all quasinormed spaces. We give a counterexample to the infinite version in for each 0 < p < 1. Some consequences for nonstandard topological vector spaces are derived.