MathDB
Problems
Contests
Undergraduate contests
Miklós Schweitzer
1978 Miklós Schweitzer
9
9
Part of
1978 Miklós Schweitzer
Problems
(1)
Miklos Schweitzer 1978_9
Source:
1/25/2009
Suppose that all subspaces of cardinality at most
ℵ
1
\aleph_1
ℵ
1
of a topological space are second-countable. Prove that the whole space is second-countable. A. Hajnal, I. Juhasz
topology