alt Hacker NewsYou implemented the problem wrong, and thus got an error. If hats is a list of colors, then every hat != green is true if the list is empty.
You implemented the problem wrong, and thus got an error. If hats is a list of colors, then every hat != green is true if the list is empty.
I wouldn’t say it is wrong per se. It certainly defies the conventional translation into FOL, but there is no a priori reason to pick the conventional formalism of FOL for this problem.