Cartesian Product of two countable set is countable.
22:21
Why do prime numbers make these spirals? | Dirichlet’s theorem and pi approximations
14:09
The union of denumerable collection of denumerable set is denumerable.
12:11
Simple Explanation of the Birthday Paradox
14:23
The set of all sequences whose elements are either zero or one is not countable.
9:30
What are Catalan Numbers?
11:59
But why is there no quintic formula? | Galois Theory
14:22
What is 0 to the power of 0?
26:12