Second-countable and T1 implies cardinality at most that of the continuum
Statement
Suppose a topological space is both a second-countable space and a T1 space. Then, its cardinality is at most equal to the cardinality of the continuum.
Facts used
- Second-countable and T1 implies perfect
- Perfect implies cardinality of space is at most the power cardinal of the cardinality of any basis
Proof
The proof follows directly by combining Facts (1) and (2).