I. Gotchev

activity

20132018

most citedCardinalities of weakly Lindelöf spaces with regular

G_{κ}

-diagonals

2 citations · 3 across the 5 of their papers we have counts for

collaborators

7 papers

math.GN2018

Cardinal inequalities for $S (n)$ -spaces

Ivan S. Gotchev

Hajnal and Juhász proved that if $X$ is a $T_{1}$ -space, then $∣ X ∣ \leq 2^{s (X) ψ (X)}$ , and if $X$ is a Hausdorff space, then $∣ X ∣ \leq 2^{c (X) χ (X)}$ and $∣ X ∣ \leq 2^{2^{s (X)}}$ . Schröder s…

math.GN2015

Regular $G_{δ}$ -diagonals and some upper bounds for cardinality of topological spaces

Ivan S. Gotchev, Mikhail G. Tkachenko, Vladimir V. Tkachuk

We prove that, under CH, any space with a regular $G_{δ}$ -diagonal and caliber $ω_{1}$ is separable; a corollary of this result answers, under CH, a question of Buzyakova. For any Urys…

math.GN2015

Generalizations of two cardinal inequalities of Hajnal and Juhász

Ivan S. Gotchev

A non-empty subset $A$ of a topological space $X$ is called \emph{finitely non-Hausdorff} if for every non-empty finite subset $F$ of $A$ and every family ${U_{x} : x \in F}$ of open…

math.GN2015★ 2 cited

Cardinalities of weakly Lindelöf spaces with regular $G_{κ}$ -diagonals

Ivan S. Gotchev

For a Urysohn space $X$ we define the regular diagonal degree $Δ (X)$ of $X$ to be the minimal infinite cardinal $κ$ such that $X$ has a regular $G_{κ}$ -diagonal i.e. there i…

math.CO2013

Path coverings with prescribed ends in faulty hypercubes

Nelson Castañeda, Ivan S. Gotchev

We discuss the existence of vertex disjoint path coverings with prescribed ends for the $n$ -dimensional hypercube with or without deleted vertices. Depending on the type of the set…

math.GN2013★ 1 cited

The non-Urysohn number of a topological space

Ivan S. Gotchev

We call a nonempty subset $A$ of a topological space $X$ finitely non-Urysohn if for every nonempty finite subset $F$ of $A$ and every family ${U_{x} : x \in F}$ of open neighborhoods…

Cardinal inequalities for S(n)-spaces

Regular Gδ​-diagonals and some upper bounds for cardinality of topological spaces

Generalizations of two cardinal inequalities of Hajnal and Juhász

Cardinalities of weakly Lindelöf spaces with regular Gκ​-diagonals

Path coverings with prescribed ends in faulty hypercubes

The non-Urysohn number of a topological space

Cardinal inequalities for $S (n)$ -spaces

Regular $G_{δ}$ -diagonals and some upper bounds for cardinality of topological spaces

Cardinalities of weakly Lindelöf spaces with regular $G_{κ}$ -diagonals