70101 Pure Mathematics
3Free topological vector space
20199 Other Mathematical Sciences
2Coproducts
2Embedding
2Free locally convex space
1Abelian groups
1Abelian topological groups
1Banach space
1Barreled space
1Cantor space
1Circle group
1Compact
1Finite-dimensional
1Frechet space
1Free abelian topological group
1Free topological group
1Hilbert cube
1Locally compact
1Locally compact abelian group

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A topological group observation on the Banach-Mazur separable quotient problem

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2019**Type:**Text , Journal article**Relation:**Topology and Its Applications Vol. 259, no. (2019), p. 283-286**Full Text:****Reviewed:****Description:**The Separable Quotient Problem of Banach and Mazur asks if every infinite-dimensional Banach space has an infinite-dimensional separable quotient Banach space. It has remained unsolved for 85 years but has been answered in the affirmative for special cases such as reflexive Banach spaces. An affirmative answer to the Separable Quotient Problem would obviously imply that every infinite-dimensional Banach space has a quotient topological group which is separable, metrizable, and infinite-dimensional in the sense of topology. In this paper it is proved that every infinite-dimensional Banach space has as a quotient group the separable metrizable infinite-dimensional topological group, T

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2019**Type:**Text , Journal article**Relation:**Topology and Its Applications Vol. 259, no. (2019), p. 283-286**Full Text:****Reviewed:****Description:**The Separable Quotient Problem of Banach and Mazur asks if every infinite-dimensional Banach space has an infinite-dimensional separable quotient Banach space. It has remained unsolved for 85 years but has been answered in the affirmative for special cases such as reflexive Banach spaces. An affirmative answer to the Separable Quotient Problem would obviously imply that every infinite-dimensional Banach space has a quotient topological group which is separable, metrizable, and infinite-dimensional in the sense of topology. In this paper it is proved that every infinite-dimensional Banach space has as a quotient group the separable metrizable infinite-dimensional topological group, T

An open mapping theorem

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2016**Type:**Text , Journal article**Relation:**Bulletin of the Australian Mathematical Society Vol. 94, no. 1 (2016), p. 65-69**Full Text:****Reviewed:****Description:**It is proved that any surjective morphism f : Z(k) -> K onto a locally compact group K is open for every cardinal k. This answers a question posed by Hofmann and the second author.

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2016**Type:**Text , Journal article**Relation:**Bulletin of the Australian Mathematical Society Vol. 94, no. 1 (2016), p. 65-69**Full Text:****Reviewed:****Description:**It is proved that any surjective morphism f : Z(k) -> K onto a locally compact group K is open for every cardinal k. This answers a question posed by Hofmann and the second author.

Embedding into free topological vector spaces on compact metrizable spaces

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2018**Type:**Text , Journal article**Relation:**Topology and its Applications Vol. 233, no. (2018), p. 33-43**Full Text:**false**Reviewed:****Description:**For a Tychonoff space X, let V(X) be the free topological vector space over X. Denote by I, G, Q and Sk the closed unit interval, the Cantor space, the Hilbert cube Q=IN and the k-dimensional unit sphere for k

Free subspaces of free locally convex spaces

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2018**Type:**Text , Journal article**Relation:**Journal of Function Spaces Vol. 2018, no. (2018), p. 1-5**Full Text:****Reviewed:****Description:**Abstract If X and Y are Tychonoff spaces, let and be the free locally convex space over and , respectively. For general and , the question of whether can be embedded as a topological vector subspace of is difficult. The best results in the literature are that if can be embedded as a topological vector subspace of , where , then is a countable-dimensional compact metrizable space. Further, if is a finite-dimensional compact metrizable space, then can be embedded as a topological vector subspace of . In this paper, it is proved that can be embedded in as a topological vector subspace if is a disjoint union of a countable number of finite-dimensional locally compact separable metrizable spaces. This is the case if It is also shown that if and denote the Cantor space and the Hilbert cube , respectively, then (i) is embedded in if and only if is a zero-dimensional metrizable compact space; (ii) is embedded in if and only if is a metrizable compact space.**Description:**If

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2018**Type:**Text , Journal article**Relation:**Journal of Function Spaces Vol. 2018, no. (2018), p. 1-5**Full Text:****Reviewed:****Description:**Abstract If X and Y are Tychonoff spaces, let and be the free locally convex space over and , respectively. For general and , the question of whether can be embedded as a topological vector subspace of is difficult. The best results in the literature are that if can be embedded as a topological vector subspace of , where , then is a countable-dimensional compact metrizable space. Further, if is a finite-dimensional compact metrizable space, then can be embedded as a topological vector subspace of . In this paper, it is proved that can be embedded in as a topological vector subspace if is a disjoint union of a countable number of finite-dimensional locally compact separable metrizable spaces. This is the case if It is also shown that if and denote the Cantor space and the Hilbert cube , respectively, then (i) is embedded in if and only if is a zero-dimensional metrizable compact space; (ii) is embedded in if and only if is a metrizable compact space.**Description:**If

Free topological vector spaces

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2017**Type:**Text , Journal article**Relation:**Topology and its Applications Vol. 223, no. (2017), p. 30-49**Full Text:**false**Reviewed:****Description:**In this paper the free topological vector space V(X) over a Tychonoff space X is defined and studied. It is proved that V(X) is a kω-space if and only if X is a kω-space. If X is infinite, then V(X) contains a closed vector subspace which is topologically isomorphic to V(N). It is proved that for X a k-space, the free topological vector space V(X) is locally convex if and only if X is discrete and countable. The free topological vector space V(X) is shown to be metrizable if and only if X is finite if and only if V(X) is locally compact. Further, V(X) is a cosmic space if and only if X is a cosmic space if and only if the free locally convex space L(X) on X is a cosmic space. If a sequential (for example, metrizable) space Y is such that the free locally convex space L(Y) embeds as a subspace of V(X), then Y is a discrete space. It is proved that V(X) is a barreled topological vector space if and only if X is discrete. This result is applied to free locally convex spaces L(X) over a Tychonoff space X by showing that: (1) L(X) is quasibarreled if and only if L(X) is barreled if and only if X is discrete, and (2) L(X) is a Baire space if and only if X is finite. © 2017 Elsevier B.V.

On varieties of Abelian topological groups with coproducts

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2017**Type:**Text , Journal article**Relation:**Bulletin of the Australian Mathematical Society Vol. 95, no. 1 (2017), p. 54-65**Full Text:**false**Reviewed:****Description:**A class of abelian topological groups was previously defined to be a variety of topological groups with coproducts if it is closed under forming subgroups, quotients, products and coproducts in the category of all abelian topological groups and continuous homomorphisms. This extended research on varieties of topological groups initiated by the second author. The key to describing varieties of topological groups generated by various classes was proving that all topological groups in the variety are a quotient of a subgroup of a product of groups in the generating class. This paper analyses generating varieties of topological groups with coproducts. It focuses on the interplay between forming products and coproducts. It is proved that the variety of topological groups with coproducts generated by all discrete groups contains topological groups which cannot be expressed as a quotient of a subgroup of a product of a coproduct of discrete groups. It is proved that the variety of topological groups with coproducts generated by any infinite-dimensional Hilbert space contains all infinite-dimensional Hilbert spaces, answering an open question. This contrasts with the result that a variety of topological groups generated by a topological group does not contain any infinite-dimensional Hilbert space of greater cardinality. © 2016 Australian Mathematical Publishing Association Inc..

Subspaces of the free topological vector space on the unit interval

- Gabriyelyan, Saak, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Morris, Sidney**Date:**2018**Type:**Text , Journal article**Relation:**Bulletin of the Australian Mathematical Society Vol. 97, no. 1 (2018), p. 110-118**Full Text:**false**Reviewed:****Description:**For a Tychonoff space X, let V(X) be the free topological vector space over X, A(X) the free abelian topological group over X and I the unit interval with its usual topology. It is proved here that if X is a subspace of I, then the following are equivalent: V(X) can be embedded in V(I) as a topological vector subspace; A(X) can be embedded in A(I) as a topological subgroup; X is locally compact. © 2017 Australian Mathematical Publishing Association Inc..

Varieties of abelian topological groups with coproducts

- Gabriyelyan, Saak, Leiderman, Arkady, Morris, Sidney

**Authors:**Gabriyelyan, Saak , Leiderman, Arkady , Morris, Sidney**Date:**2015**Type:**Text , Journal article**Relation:**Algebra Universalis Vol. 74, no. 3-4 (2015), p. 241-251**Full Text:**false**Reviewed:****Description:**Varieties of groups, introduced in the 1930s by Garret Birkhoff and B.H. Neumann, are defined as classes of groups satisfying certain laws or equivalently as classes of groups closed under the formation of subgroups, quotient groups, and arbitrary cartesian products. In the 1960s the third author introduced varieties of topological groups as classes of (not necessarily Hausdorff) topological groups closed under subgroups, quotient groups and cartesian products with the Tychonoff topology. While there is only a countable number of varieties of abelian groups, there is a proper class of varieties of abelian topological groups. We observe that while every variety of abelian groups is closed under abelian coproducts, varieties of abelian topological groups are in general not closed under abelian coproducts with the coproduct topology. So this paper studies varieties of abelian topological groups which are also closed under abelian coproducts with the coproduct topology. Noting that the variety of all abelian groups is singly generated, that is, it is the smallest variety containing some particular group, but that the variety of all abelian topological groups is not singly generated, it is proved here that the variety of all abelian topological groups with coproducts is indeed singly generated. There is much literature describing varieties of topological groups generated by various classical topological groups, and the study of varieties with coproducts generated by particular classical topological groups is begun here. Some nice results are obtained about those varieties of abelian topological groups with coproducts which are also closed with regard to forming Pontryagin dual groups. © 2015, Springer Basel.

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