Irresolvable countable spaces of weight less than
We construct in Bell-Kunen’s model: (a) a group maximal topology on a countable infinite Boolean group of weight and (b) a countable irresolvable dense subspace of . In this model .
Is the product of ccc spaces a ccc space?
In this expository paper it is shown that Martin's Axiom and the negation of the Continuum Hypothesis imply that the product of ccc spaces is a ccc space. The Continuum Hypothesis is then used to construct the Laver-Gavin example of two ccc spaces whose product is not a ccc space.
Is 𝓟(ω) a subalgebra?
We consider the question of whether 𝒫(ω) is a subalgebra whenever it is a quotient of a Boolean algebra by a countably generated ideal. This question was raised privately by Murray Bell. We obtain two partial answers under the open coloring axiom. Topologically our first result is that if a zero-dimensional compact space has a zero-set mapping onto βℕ, then it has a regular closed zero-set mapping onto βℕ. The second result is that if the compact space has density at most ω₁, then it will map onto...
Ishikawa iteration process with errors for nonexpansive mappings in uniformly convex Banach spaces.
Isolated points and redundancy
We describe the isolated points of an arbitrary topological space . If the -specialization pre-order on has enough maximal elements, then a point is an isolated point in if and only if is both an isolated point in the subspaces of -kerneled points of and in the -closure of (a special case of this result is proved in Mehrvarz A.A., Samei K., On commutative Gelfand rings, J. Sci. Islam. Repub. Iran 10 (1999), no. 3, 193–196). This result is applied to an arbitrary subspace of the prime...
Isometric embeddings and universal spaces.
Isometric embeddings of a class of separable metric spaces into Banach spaces
Let be a bounded countable metric space and a constant, such that , for any pairwise distinct points of . For such metric spaces we prove that they can be isometrically embedded into any Banach space containing an isomorphic copy of .
Isometric Embeddings of Pro-Euclidean Spaces
In [12] Petrunin proves that a compact metric space X admits an intrinsic isometry into En if and only if X is a pro-Euclidean space of rank at most n, meaning that X can be written as a “nice” inverse limit of polyhedra. He also shows that either case implies that X has covering dimension at most n. The purpose of this paper is to extend these results to include both embeddings and spaces which are proper instead of compact. The main result of this paper is that any pro-Euclidean space of rank...
Isometrien des Konvexringes
Isometrien in metrischen Vektorräumen
Isometries in ordered groups
Isometries of Measure Algebras.
Isometry groups of non standard metric products
We consider isometry groups of a fairly general class of non standard products of metric spaces. We present sufficient conditions under which the isometry group of a non standard product of metric spaces splits as a permutation group into direct or wreath product of isometry groups of some metric spaces.
Isomorphism of spaces of bounded continuous functions
Isomorphism Problems for the Baire Function Spaces of Topological Spaces
Let a compact Hausdorff space X contain a non-empty perfect subset. If α < β and β is a countable ordinal, then the Banach space Bα (X) of all bounded real-valued functions of Baire class α on X is a proper subspace of the Banach space Bβ (X). In this paper it is shown that: 1. Bα (X) has a representation as C(bα X), where bα X is a compactification of the space P X – the underlying set of X in the Baire topology generated by the Gδ -sets in X. 2. If 1 ≤ α < β ≤ Ω, where Ω is the first...
Isomorphismen, topologische Maßräume.
Isomorphisms of products
Isomorphisms of products of weakly homogeneous spaces
Iterated and double limits
Itération des polynômes et propriétés d'orthogonalité