Thanks Yoav, I think I forgot the definition of the identity profunctor and was thinking it imposed equality between inputs and outputs, but of course that violates the definition of a profunctor.

> On a stylistic note, I think 0 is better than 1 as the name for the only element in 1, as John used in the last lecture. I've seen others here use a bullet or star symbol, which I think are also better than 1.

I couldn't remember and got lazy so I didn't look up what we had used before. I'll change that