Double Pointed Fortissimo Space is Lindelöf
From ProofWiki
Theorem
Let $T = \left({S, \tau}\right)$ be a Fortissimo space.
Let $T \times D$ be the double pointed topology on $T$.
Then $T \times D$ is a Lindelöf space.
Proof
Sources
- Lynn Arthur Steen and J. Arthur Seebach, Jr.: Counterexamples in Topology (1970)... (previous)... (next): $\text{II}: \ 25: \ 4$