Sur les sous-espaces spectraux d'un opérateur compact relativement à une algèbre de von Neumann
Soit un opérateur compact dans une algèbre de Von Neumann. On montre que le sous-espace sup ker est relativement fini.
Soit un opérateur compact dans une algèbre de Von Neumann. On montre que le sous-espace sup ker est relativement fini.
In this work we discuss several ways to extend to the context of Banach spaces the notion of Hilbert-Schmidt operator: p-summing operators, γ-summing or γ-radonifying operators, weakly* 1-nuclear operators and classes of operators defined via factorization properties. We introduce the class PS₂(E;F) of pre-Hilbert-Schmidt operators as the class of all operators u: E → F such that w ∘ u ∘ v is Hilbert-Schmidt for every bounded operator v: H₁ → E and every bounded operator w: F → H₂, where H₁ and...
We prove existence (uniqueness is easy) of a weak solution to a boundary value problem for an equation like where the function is only supposed to be locally lipschitz continuous. In order to replace the lack of compactness in t on v<1, we use nonlinear semigroup theory.