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.