Ordered vector spaces E and F are said to be order isomorphic if there is a (not necessarily linear) bijection between them that preserves order. We investigate some situations under which an order isomorphism between two Banach lattices implies the persistence of some linear lattice structure. For instance, it is shown that if a Banach lattice E is order isomorphic to C(K) for some compact Hausdorff space K, then E is (linearly) isomorphic to C(K) as a Banach lattice. Similar results hold for Banach lattices order isomorphic to c_0, and for Banach lattices that contain a closed sublattice order isomorphic to c_0.
Some equivalence relations which are Borel reducible to isomorphism between separable Banach spaces
我们将有关可分巴拿赫空间之间同构关系复杂性的已知结果改进为Borel可约性，并且我们使用经典空间$c_0$、$\ell_p$和$L_p$、$1 \leq p <2$实现了这一点。更准确地说，我们表明，关系$E_{K_σ}$是Borel可约同构和补充双嵌入之间的$c_0$或$\ell_p, 1 \leq p <2$的子空间。我们证明了关系$E_{K_σ} \otimes =^+$是Borel可约的同构，补双嵌入，和Lipschitz等价的子空间之间的$L_p, 1 \leq p <2$。
Let $K_1$, $K_2$ be compact Hausdorff spaces and $E_1, E_2$ be Banach spaces not containing a copy of $c_0$. We establish lower estimates of the Banach-Mazur distance between the spaces of continuous functions $\mathcal{C}(K_1, E_1)$ and $\mathcal{C}(K_2, E_2)$ based on the ordinals $ht(K_1)$, $ht(K_2)$, which are new even for the case of spaces of real valued functions on ordinal intervals. As a corollary we deduce that $\mathcal{C}(K_1, E_1)$ and $\mathcal{C}(K_2, E_2)$ are not isomorphic if $ht(K_1)$ is substantially different from $ht(K_2)$.
Let \(X\) be a compact metric space and \(E\) be a Banach space. \(\lip (X, E)\) denotes the Banach space of all \(E\)-valued little Lipschitz functions on \(X\). We show that \(\lip (X, E)^{**}\) is isometrically isomorphic to Banach space of \(E^{**}\)-valued Lipschitz functions \(\Lip(X, E^{**})\) under several conditions. Moreover, we describe the isometric isomorphism from \(\lip (X, E)^{**}\) to \(\Lip (X, E^{**})\).
Banach non-isomorphism of type III and semifinite noncommutative $L_p$-spaces
Institute for Advanced Study in Mathematics of HIT, Harbin Institute of Technology（哈尔滨工业大学数学学院）；School of Mathematics and Statistics, University of NSW（新南威尔士大学数学与统计学院）
The paper alluded to in the title contains the following striking result: Let $I$ be the unit interval and $Δ$ the Cantor set. If $X$ is a quasi Banach space containing no copy of $c_0$ which is isomorphic to a closed subspace of a space with a basis and $C(I, X)$ is linearly homeomorphic to $C(Δ, X)$, then $X$ is locally convex, i.e., a Banach space. It is shown that Kalton result is sharp by exhibiting non locally convex quasi Banach spaces X with a basis for which $C(I, X)$ and $C(Δ, X)$ are isomorphic. Our examples are rather specific and actually in all cases X is isomorphic to $C(Δ, X)$ …
证明了任何巴拿赫空间都包含一个非同构子空间或极小子空间的连续统。定义了一个遍历Banach空间$X$，使$E_0$ Borel在$X$的子空间集合上同构，并证明了每个Banach空间要么是遍历的，要么包含一个具有无条件基$ which is complementably universal for the family of its block-subspaces. We also use our methods to get uniformity results; for example, in combination with a result of B. Maurey, V. Milman and N. Tomczak-Jaegermann, we show that an unconditional basis of a Banach space, of which every block-subspace is complemented, must be asymptotically $ c_0 $ or $ l_p $的子空间.
Ring isomorphisms in norm between Banach algebras of continuous functions
Graduate School of Science and Technology, Niigata University（新潟大学理工学研究科）；Department of Mathematics, Faculty of Science, Niigata University（新潟大学理学部数学系）
Spectral-free methods in the theory of hereditarily indecomposable Banach spaces
给出了遗传不可分解巴拿赫空间的一些经典性质的新的简单证明，包括W. T. Gowers和B. Maurey证明了一个遗传不可分解的巴拿赫空间不能同构于它自身的一个真子空间。这些证明不使用谱理论，因此，它们在实空间和复空间中都有效。我们用我们的方法证明了一些新的结果。例如，我们给出了Gowers和Maurey的后一个结果的定量版本，并推导出与所有子空间等距的巴拿赫空间应该有一个无条件基，其无条件常数任意接近$1$。我们还研究了遗传不可分解空间中同构之间的同伦关系。
Lifting properties for Banach spaces are studied. An alternate version of the lifting property due to Lindenstrass and Tzafriri is proposed and a characterization, up to isomorphism, is given. The quotient lifting property for pairs of Banach spaces $(X,J)$, with $J$ proximinal in $X$, is considered and several conditions for the property to hold are given.
A remarkable result of Molnár [Proc. Amer. Math. Soc., 126 (1998), 853-861] states that automorphisms of the algebra of operators acting on a separable Hilbert space is stable under "small" perturbations. More precisely, if $ϕ,ψ$ are endomorphisms of $\mathcal{B}(\mathcal{H})$ such that $\|ϕ(A)-ψ(A)\|<\|A\|$ and $ψ$ is surjective then so is $ϕ$. The aim of this paper is to extend this result to a larger class of Banach spaces including $\ell_p$ and $L_p$ spaces ($1<p<+\infty$). En route to the proof we show that for any Banach space $X$ from the above class all faithful, unital, separable, ref…
