# Today I Learned

Some of the things I've learned every day since Oct 10, 2016

## 98: Top Type, Bottom Type

Given a type system, the top type $\top$ is the type which contains every possible value in that type system, making every other type a subtype of $\top$.

By contrast, the bottom type $\bot$ is the type which contains no values, making every other type a supertype of $\bot$.