nice-topology-suppose-S-is-Baire-s-space-and-S-n-1-F-n-such-that-F-n-s-are-closed-sets-prove-that-m-F-m-m-n-j

Question Number 115285 by mnjuly1970 last updated on 28/Sep/20

\dots ♠ n i c e t o p o l o g y ♠ \dots

s u p p o s e ⟨ S, τ ⟩ i s {B a i r e}^{'} s

s p a c e a n d

S = \underset{n = 1}{\overset{\infty}{\cup}} F_{n} s u c h

t h a t F_{n}^{'} s a r e c l o s e d s e t s

p r o v e t h a t ::

\exists m; F_{m}^{°} \neq \emptyset . . m . n . j u l y

\dots ♣ m . n . j u l y . 1970 ♣ \dots