Limit points of subsequences
General Topology
2019-06-13 v2 Functional Analysis
Probability
Abstract
Let be a sequence taking values in a separable metric space and be a generalized density ideal or an -ideal on the positive integers (in particular, can be any Erd{\H o}s--Ulam ideal or any summable ideal). It is shown that the collection of subsequences of which preserve the set of -cluster points of [respectively, -limit points] is of second category if and only if the set of -cluster points of [resp., -limit points] coincides with the set of ordinary limit points of ; moreover, in this case, it is comeager. In particular, it follows that the collection of subsequences of which preserve the set of ordinary limit points of is comeager.
Cite
@article{arxiv.1801.00343,
title = {Limit points of subsequences},
author = {Paolo Leonetti},
journal= {arXiv preprint arXiv:1801.00343},
year = {2019}
}
Comments
To appear in Topology Appl. arXiv admin note: substantial text overlap with arXiv:1711.04265