> <small>In Category Theory discussion, the Monad Laws are instead expressed in terms of `join` (which they call `μ`) and `mid` (which they call `η`). These are assumed to be "natural transformations" for their box type, which means that they satisfy these equations with that box type's `map`:
> <pre>map f ○ mid == mid ○ f<br>map f ○ join == join ○ map (map f)</pre>
> <small>In Category Theory discussion, the Monad Laws are instead expressed in terms of `join` (which they call `μ`) and `mid` (which they call `η`). These are assumed to be "natural transformations" for their box type, which means that they satisfy these equations with that box type's `map`:
> <pre>map f ○ mid == mid ○ f<br>map f ○ join == join ○ map (map f)</pre>