We survey recent results on the structure of the range of the derivative of a smooth real valued function f defined on a real Banach space X and of a smooth mapping F between two real Banach spaces X and Y. We recall some necessary conditions and some sufficient conditions on a subset A of L(X,Y) for the existence of a Fréchet-differentiable mapping F from X into Y so that F'(X) = A. Whenever F is only assumed Gâteaux-differentiable, new phenomena appear: we discuss the existence of a mapping F...

This article is devoted to an extension of Simons' inequality. As a consequence, having a pointwise converging sequence of functions, we get criteria of uniform convergence of an associated sequence of functions.

We prove that if f is a real valued lower semicontinuous function
on a Banach space X and if there exists a C^1, real valued Lipschitz continuous
function on X with bounded support and which is not identically equal to zero,
then f is Lipschitz continuous of constant K provided all lower subgradients of
f are bounded by K. As an application, we give a regularity result of viscosity
supersolutions (or subsolutions) of Hamilton-Jacobi equations in infinite dimensions
which satisfy a coercive condition....

Download Results (CSV)