[HTML][HTML] Ideals on countable sets: a survey with questions
C Uzcátegui Aylwin - Revista Integración, 2019 - scielo.org.co
An ideal on a set X is a collection of subsets of X closed under the operations of taking finite
unions and subsets of its elements. Ideals are a very useful notion in topology and set theory …
unions and subsets of its elements. Ideals are a very useful notion in topology and set theory …
[HTML][HTML] Analytic P-ideals and Banach spaces
P Borodulin-Nadzieja, B Farkas - Journal of Functional Analysis, 2020 - Elsevier
We study the interplay between Banach space theory and theory of analytic P-ideals.
Applying the observation that, up to isomorphism, all Banach spaces with unconditional …
Applying the observation that, up to isomorphism, all Banach spaces with unconditional …
Regular matrices of unbounded linear operators
P Leonetti - Proceedings of the Royal Society of Edinburgh Section …, 2024 - cambridge.org
Let-convergent (and bounded). This allows us to establish the relationship between the
classical Silverman–Toeplitz characterization of regular matrices and its multidimensional …
classical Silverman–Toeplitz characterization of regular matrices and its multidimensional …
[HTML][HTML] Topological representations
This paper studies the combinatorics of ideals which recently appeared in ergodicity results
for analytic equivalence relations. The ideals have the following topological representation …
for analytic equivalence relations. The ideals have the following topological representation …
[HTML][HTML] Limit points of subsequences
P Leonetti - Topology and its Applications, 2019 - Elsevier
Let x be a sequence taking values in a separable metric space and let I be an F σ δ-ideal on
the positive integers (in particular, I can be any Erdős–Ulam ideal or any summable ideal). It …
the positive integers (in particular, I can be any Erdős–Ulam ideal or any summable ideal). It …
Different kinds of density ideals
J Tryba - Journal of Mathematical Analysis and Applications, 2021 - Elsevier
The paper considers several different kinds of ideals defined by some densities. We depict
relationships between Erdős-Ulam, density, matrix summability and generalized density …
relationships between Erdős-Ulam, density, matrix summability and generalized density …
On some locally convex FK spaces
P Leonetti, C Orhan - Topology and its Applications, 2022 - Elsevier
We provide necessary and/or sufficient conditions on vector spaces V of real sequences to
be a Fréchet space such that each coordinate map is continuous, that is, to be a locally …
be a Fréchet space such that each coordinate map is continuous, that is, to be a locally …
[HTML][HTML] HL ideals and Sacks indestructible ultrafilters
We study ultrafilters on countable sets and reaping families which are indestructible by
Sacks forcing. We deal with the combinatorial characterization of such families and we prove …
Sacks forcing. We deal with the combinatorial characterization of such families and we prove …
On the structure of Borel ideals in-between the ideals ED and Fin⊗ Fin in the Katětov order
For a family F⊆ ω ω we define the ideal I (F) on ω× ω to be the ideal generated by the family
{A⊆ ω× ω:∃ f∈ F∀∞ n (|{k:(n, k)∈ A}|≤ f (n))}. Using ideals of the form I (F), we show that …
{A⊆ ω× ω:∃ f∈ F∀∞ n (|{k:(n, k)∈ A}|≤ f (n))}. Using ideals of the form I (F), we show that …
Strong universality, recurrence, and analytic P-ideals in dynamical systems
P Leonetti - arXiv preprint arXiv:2401.01131, 2024 - arxiv.org
Given a dynamical system $(X, T) $ and a family $\mathsf {I}\subseteq\mathcal {P}(\omega) $
of" small" sets of nonnegative integers, a point $ x\in X $ is said to be $\mathsf {I} $-strong …
of" small" sets of nonnegative integers, a point $ x\in X $ is said to be $\mathsf {I} $-strong …