Unconditionally converging holomorphic mappings between Banach spaces
We investigate sequences and operators via the unconditionally p-summable sequences. We characterize the unconditionally p-null sequences in terms of a certain tensor product and then prove that, for every 1 ≤ p < ∞, a subset of a Banach space is relatively unconditionally p-compact if and only if it is contained in the closed convex hull of an unconditionally p-null sequence.
Let X be a Banach space. We study the circumstances under which there exists an uncountable set 𝓐 ⊂ X of unit vectors such that ||x-y|| > 1 for any distinct x,y ∈ 𝓐. We prove that such a set exists if X is quasi-reflexive and non-separable; if X is additionally super-reflexive then one can have ||x-y|| ≥ slant 1 + ε for some ε > 0 that depends only on X. If K is a non-metrisable compact, Hausdorff space, then the unit sphere of X = C(K) also contains such a subset; if moreover K is perfectly...
An application of Mittag-Leffler lemma in the category of quotients of Fréchet spaces. We use Mittag-Leffler Lemma to prove that for a nonempty interval , the restriction mapping is surjective and we give a corollary.
On présente une formule explicite pour la constante de Sobolev logarithmique correspondant à des diffusions réelles ou à des processus entiers de vie et de mort, sous l’hypothèse que certaines quantités, naturellement associées à des inégalités de Hardy dans ce contexte, approchent leur supremum au bord de leur domaine de définition. La preuve se ramène au cas de la constante de Poincaré, à l’aide de comparaisons exactes entre entropie et variances appropriées.