interpretation "three" 'three = (Var (S (S (S O)))).
notation "𝟜" non associative with precedence 90 for @{ 'four }.
interpretation "four" 'four = (Var (S (S (S (S O))))).
interpretation "three" 'three = (Var (S (S (S O)))).
notation "𝟜" non associative with precedence 90 for @{ 'four }.
interpretation "four" 'four = (Var (S (S (S (S O))))).