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Banach spaces, function spaces, real functions, integral transforms, theory of distributions, measure theory.

3 votes
1 answer
225 views

Is compact-open topology stable with respect to injective limits?

Let $X$ be a locally convex space, and $\{Y_i;\ i\in I\}$ a covariant system of locally convex spaces over a partially ordered set $I$, i.e. a system of linear continuous mappings is given $\sigma^j_i …
Sergei Akbarov's user avatar
3 votes
1 answer
333 views

Is there an operation in topology analogous to the operation of averaging over a compact sub...

Let me start with the following Illustration: Let $G$ be a compact group, and let $\pi:G\to H$ be its (surjective) continuous homomorphism onto a (compact) group $H$. So we can think that $H$ is the …
Sergei Akbarov's user avatar
2 votes
1 answer
261 views

Qualitative difference between "continuous" and "discontinuous" states on $M(G)$

Let $G$ be a locally compact Abelian group (we can think that $G={\mathbb R}$). Let $C_0(G)$ be the space of continuous functions $u:G\to{\mathbb C}$ vanishing at infinity with the usual $\sup$-norm, …
Sergei Akbarov's user avatar
3 votes
0 answers
153 views

Is it possible to reconstruct the universally measurable sets in X from the $C^*$-algebra $C...

This continues my question of two months ago. Let $X$ be a compact Hausdorff topological space. We consider the $C^*$-algebra $C(X)$ of continuous functions on $X$, its dual space $C(X)^{*}=M(X)$ of m …
Sergei Akbarov's user avatar
3 votes
1 answer
693 views

Completions of $C(X)$ with respect to the topologies generated by states

I have no intuition in this field so excuse me if this is trivial. Let $X$ be a compact Hausdorff space, and $C(X)$ the algebra of continuous functions on $X$ with the usual $\sup$-norm. This is a $C^ …
Sergei Akbarov's user avatar
3 votes
0 answers
228 views

Is it possible to reconstruct the compact space $X$ from the space of measures $M(X)$?

Let $X$ be a compact Hausdorff topological space and $C(X)$ the Banach algebra of continuous functions $u:X\to\mathbb C$ (with the usual $\sup$-norm). It is well-known that the structure of Banach alg …
Sergei Akbarov's user avatar
2 votes

Pontryagin-reflexivity of spaces of continuous functions

I would say that this is not well-known: It is well-known that a Banach space $V$ is always Pontryagin-reflexive, i.e. the natural map $V\to \text{Hom}_\mathbb{R}(\text{Hom}_\mathbb{R}(V, \mathbb{R}) …
Sergei Akbarov's user avatar
3 votes
1 answer
156 views

$\varepsilon$-product in Bierstedt's paper

I am reading K.D.Bierstedt's paper Gewichtete Räume stetiger vektorwertiger Funktionen und das injektive Tensorprodukt. I. Journal für die reine und angewandte Mathematik 259 (1973): 186-210. It is wr …
Sergei Akbarov's user avatar
3 votes
0 answers
114 views

Approximation of a linear functional by linear continuous functionals

Let $X$ be a locally convex space, $T$ a balanced convex compact set in $X$, and $f:X\to\mathbb{C}$ a linear functional which is (not necessarily continuous on $X$, but) continuous on $T$. It is not d …
Sergei Akbarov's user avatar
3 votes
0 answers
153 views

What do people call functionals on holomorphic functions and on polynomials?

There are four most important functional spaces in analysis: the space $\mathcal{C}(M)$ of continuous functions on a topological space, the space $\mathcal{E}(M)$ of smooth functions on a smooth man …
Sergei Akbarov's user avatar
4 votes
0 answers
194 views

Approximation of a holomorphic function vanishing at a submanifold by polynomials

Suppose $M$ is a complex affine algebraic manifold in ${\mathbb C}^n$ (I mean, a set of common zeroes of a system of polynomials on ${\mathbb C}^n$, which is at the same time a smooth manifold). Consi …
Sergei Akbarov's user avatar
4 votes

Function spaces satisfying $\mathcal{F}(M\times N)\simeq\mathcal{F}(M)\otimes\mathcal{F}(N)$

In the theory of stereotype spaces there is a series of natural functors that satisfy this identity with one of the two main tensor products (the so-called ``injective stereotype tensor product'' $\od …
Sergei Akbarov's user avatar
5 votes
1 answer
209 views

Are linear continuous mappings open on totally bounded sets?

Let $X$ and $Y$ be locally convex spaces, and $\varphi: X\to Y$ a linear continuous mapping. Suppose first that $S$ is a compact set in $X$. Then $\varphi$, being considered as a mapping from $S$ to $ …
Sergei Akbarov's user avatar
4 votes
4 answers
745 views

On Köthe sequence spaces

I asked this a week ago at math.stackexchange, but without success. As far as I understand, there are several meanings of the notion of the Köthe sequence space, in particular, Hans Jarchow in his "L …
Sergei Akbarov's user avatar
1 vote
0 answers
73 views

"Constructive" proof that compact sets $K\subseteq L_1(\mu\times\nu)$ are contained in produ...

A.Defant and K.Floret in chapter 7 of their Tensor Norms and Operator Ideals prove the equality $$ L_1(\mu\times\nu)\cong L_1(\mu)\widehat{\otimes}L_1(\nu) $$ for measures $\mu$ and $\nu$. At the same …
Sergei Akbarov's user avatar

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