Better Subtopologies
We study conditions under which a space that has a good property and a courser topology with another good property admits a continuous bijection onto a space with both properties.
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arXiv subjects
Raushan Buzyakova
Publications and source records attributed to Raushan Buzyakova.
On Topological Groups of Automorphisms
We study spaces $X$ for which the space $Hom_p(X)$ of automorphisms with the topology of point-wise convergence is a topological group. We identify large classes of spaces $X$ for which $Hom_p(X)$ is or is not a topological group.
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On Topological Groups of Automorphisms on Unions
We study groups of homeomorphic bijections on spaces that are finite unions of compact connected linearly ordered subsets. We prove that all such groups when endowed with the topology of point-wise convergence are topological groups. }
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A Glance into the Anatomy of Monotonic Maps
Given an autohomeomorphism on an ordered topological space or its subspace, we show that it is sometimes possible to introduce a new topology-compatible order on that space so that the same map is monotonic with respect to the new ordering. We note that the existence of such a re-ordering for a given map is equivalent to the map being conjugate (topologically equivalent) to a monotonic map on some homeomorphic ordered space. We observe that the latter cannot always be chosen to be order-isomorphic to the original space. Also, we identify other routes that may lead to similar affirmative statements for other classes of spaces and maps.
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On Topological Groups of Monotonic Autohomeomorphisms
We study topological groups of monotonic autohomeomorphisms on a generalized ordered space $L$. We find a condition that is necessary and sufficient for the set of all monotonic autohomeomorphisms on $L$ along with the function composition and the topology of point-wise convergence to be a topological group.
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On Homeomorphisms of Function Spaces Over Products with Compacta
We show that if $C_p(X\times Z)$ is homeomorphic to $C_p(Y\times Z)$, where $Z$ is compact, and $X$ and $Y$ are of countable netweight, then $C_p(X\times M)$ is homeomorphic to $C_p(Y\times M)$ for some metric compactum $M$.
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Function Spaces over Products with Ordinals
We are concerned with the question of when a homeomorphism between $C_p(X\times τ)$ and $C_p(Y\times τ)$ implies the existence of a homeomorphism between $C_p(X\times τ')$ and $C_p(Y\times τ')$, where $τ$ and $τ'$ are spaces of ordinals with some additional desired properties.
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A Note on Minimal Separating Function Sets
We study point-separating function sets that are minimal with respect to the property of being separating. We first show that for a compact space $X$ having a minimal separating function set in $C_p(X)$ is equivalent to having a minimal separating collection of functionally open sets in $X$. We also identify a nice visual property of $X^2$ that may be responsible for the existence of a minimal separating function family for $X$ in $C_p(X)$. We then discuss various questions and directions around the topic.
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When is $X\times Y$ homeomorphic to $X\times_l Y$?
We identify a class of linearly ordered topological spaces $X$ that may satisfy the property that $X\times X$ is homeomorphic to $X\times_l X$ or can be embedded into a linearly ordered space with the stated property. We justify the conjectures by partial results.
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A Note On Separating Function Sets
We study separating function sets. We find some necessary and sufficient conditions for $C_p(X)$ or $C_p^2(X)$ to have a point-separating subspace that is a metric space with certain nice properties. One of the corollaries to our discussion is that for a zero-dimensional $X$, $C_p(X)$ has a discrete point-separating space if and only if $C_p^2(X)$ does.
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Three Questions on Special Homeomorphisms on Subgroups of $R$ and $R^\infty$
We provide justifications for two questions on special maps on subgroups of the reals. We will show that the questions can be treated from different points of view. We also discuss two versions of Anderson's Involution Conjecture.
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On Monotonic Fixed-Point Free Bijections on Subgroups of $\mathbb R$
We show that for any continuous monotonic fixed-point free automorphism $f$ on a $σ$-compact subgroup $G\subset \mathbb R$ there exists a binary operation $+_f$ such that $\langle G, +_f\rangle$ is a topological group topologically isomorphic to $\langle G, +\rangle$ and $f$ is a shift with respect to $+_f$. We then show that monotonicity cannot be replaced by the property of being periodic-point free. We explore a few routes leading to generalizations and counterexamples.
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Factorization of Bijections onto Ordered Spaces
We identify a class of subspaces of ordered spaces $\mathcal L$ for which the following statement holds: If $f:X\to L\in \mathcal L$ is a continuous bijections of a zero-dimensional space $X$, then $f$ can be re-routed via a zero-dimensional subspace of an ordered space that has weight not exceeding that of $L$.
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Stationary Sets in Topological and Paratopological Groups
We show that if a topological or paratopological group $G$ contains a stationary subset of some regular uncountable cardinal, then $G$ contains a subspace which is not collectionwise normal. This statement implies that if a monotonically normal space (in particular, any generalized ordered space) is a paratopological group then the space is hereditarily paracompact.
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On Hereditarily Normal Topological Groups
In this paper we investigate hereditarily normal topological groups and their subspaces. We prove that every compact subspace of a hereditarily normal topological group is metrizable. To prove this statement we first show that a hereditarily normal topological group with a non-trivial convergent sequence has $G_δ$-diagonal. This implies, in particular, that every countably compact subset of a hereditarily normal topological group with a non-trivial convergent sequence is metrizable. Another corollary is that under the Proper Forcing Axiom, every countably compact subset of a hereditarily normal topological group is metrizable.
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On multivaled fixed-point free maps on R^n
To formulate our results let $f$ be a continuous map from $\mathbb R^n$ to $2^{\mathbb R^n}$ and $k$ a natural number such that $|f(x)|\leq k$ for all $x$. We prove that $f$ is fixed-point free if and only if its continuous extension $\tilde f:β\mathbb R^n\to 2^{β\mathbb R^n}$ is fixed-point free. If one wishes to stay within metric terms, the result can be formulated as follows: $f$ is fixed-point free if and only if there exists a continuous fixed-point free extension $\bar f: b\mathbb R^n\to 2^{b\mathbb R^n}$ for some metric compactificaton $b\mathbb R^n$ of $\mathbb R^n$. Using the classical notion of colorablity, we prove that such an $f$ is always colorable. Moreover, a number of colors sufficient to paint the graph can be expressed as a function of $n$ and $k$ only. The mentioned results also hold if the domain is replaced by any closed subspace of $\mathbb R^n$ without any changes in the range.
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