We give characterizations of the distributional derivatives $D^{1,1}$, $D^{1,0}$, $D^{0,1}$ of functions of two variables of locally finite variation. Then we use these results to prove the existence theorem for the hyperbolic equation with a nonhomogeneous term containing the distributional derivative determined by an additive function of an interval of finite variation. An application of the above theorem to a hyperbolic equation with an impulse effect is also given.

In this note we establish a vector-valued version of Beurling’s theorem (the Lax-Halmos theorem) for the polydisc. As an application of the main result, we provide necessary and sufficient conditions for the “weak” completion problem in $H^{\infty }\left(ⁿ\right)$.

On étudie ici quelques espaces de fonctions holomorphes dans des domaines localement convexes, ayant comme cas particuliers les espaces de Fock holomorphes. Les espaces duaux sont caractérisés avec la transformation de Fourier-Borel pour des types d’holomorphie appropriés. On montre que ces espaces de fonctions sont de Fréchet-Schwartz (resp. de Silva, resp. nucléaires) quand leurs domaines sont des espaces de Silva (resp. de Fréchet-Schwartz, resp. nucléaires). Les conditions de croissance $p$-sommable...

Let $X$ be a completely regular Hausdorff space, $E$ a real normed space, and let $C_b(X,E)$ be the space of all bounded continuous $E$-valued functions on $X$. We develop the general duality theory of the space $C_b(X,E)$ endowed with locally solid topologies; in particular with the strict topologies ${\beta }_z(X,E)$ for $z=\sigma ,\tau ,t$. As an application, we consider criteria for relative weak-star compactness in the spaces of vector measures $M_z(X,E^{\text{'}})$ for $z=\sigma ,\tau ,t$. It is shown that if a subset $H$ of $M_z(X,E^{\text{'}})$ is relatively $\sigma (M_z(X,E^{\text{'}}),C_b(X,E))$-compact, then the set $conv\left(S\right(H\left)\right)$ is still relatively $\sigma (M_z(X,E^{\text{'}}),C_b(X,E))$-compact...

If $(\Omega ,\Sigma )$ is a measurable space and $X$ a Banach space, we provide sufficient conditions on $\Sigma$ and $X$ in order to guarantee that $\mathrm{b}vca(\Sigma ,X)$, the Banach space of all $X$-valued countably additive measures of bounded variation equipped with the variation norm, contains a copy of $c_0$ if and only if $X$ does.

Let X be an infinite-dimensional complex Banach space. Very recently, several results on the existence of entire functions on X bounded on a given ball B₁ ⊂ X and unbounded on another given ball B₂ ⊂ X have been obtained. In this paper we consider the problem of finding entire functions which are uniformly bounded on a collection of balls and unbounded on the balls of some other collection.

We discuss equivariance for linear liftings of measurable functions. Existence is established when a transformation group acts amenably, as e.g. the Möbius group of the projective line. Since the general proof is very simple but not explicit, we also provide a much more explicit lifting for semisimple Lie groups acting on their Furstenberg boundary, using unrestricted Fatou convergence. This setting is relevant to $L^{\infty }$-cocycles for characteristic classes.