Thanks for catching all those typos, Dan!

> 3. In puzzle 207, I think the feasibility relations compose the other way around, that is, it should have been \\(\Phi \Psi : \mathbb{N} \nrightarrow [0,\infty) \\).

Ugh - yes! But since I'd just been talking about \\(\Psi\Phi\\) in a general abstract situation, I want my example to be about a feasibility relation called \\(\Psi\Phi\\) . So I'm going to switch the names \\(\Phi\\) and \\(\Psi\\) in puzzles 205 and 206.

Sorry! Things are already confusing enough, given that this feasibility relation



is called \\(\Psi\Phi\\). That's because when we apply first a function \\(f\\) and then a function \\(g\\), we usually call the composite \\(g f\\) or \\(g \circ f\\).