DOI: 10.68381/jca15031 ISSN: 0944-6532

Pseudometrizable Bornological Convergence is Attouch-Wets Convergence

Gerald Beer, Sandro Levi

Let

\mathcal{S} S
be an ideal of subsets of a metric space
\langle X,d \rangle ⟨ X , d ⟩
. A net of subsets
\langle A_\lambda\rangle ⟨ A λ ⟩
of
X X
is called
\mathcal{S} S
-convergent to a subset
A A
of
X X
if for each
S \in \mathcal{S} S ∈ S
and each
\varepsilon > 0 ε > 0
, we have eventually
A \cap S \subseteq A^\varepsilon_\lambda \ \textrm{and} \ A_\lambda \cap S \subseteq A^\varepsilon. A ∩ S ⊆ A λ ε  and  A λ ∩ S ⊆ A ε .
We identify necessary and sufficient conditions for this convergence to be admissible and topological on the power set of
X X
. We show that
\mathcal{S} S
-convergence is compatible with a pseudometrizable topology if and only if
\mathcal{S} S
has a countable base and each member of
\mathcal{S} S
has an
\varepsilon ε
-enlargement that is again in
\mathcal{S} S
. Further, in the case that the ideal is a bornology, we show that
\mathcal{S} S
-convergence when pseudometrizable is Attouch-Wets convergence with respect to an equivalent metric.