for n being Nat
for s being set
for S1, S2 being BoolSignature st the bool-sort of S1 = the bool-sort of S2 & len the connectives of S2 >= 3 & ( for i being Nat st i >= 1 & i <= 3 holds
( the Arity of S1 . ( the connectives of S1 . i) = the Arity of S2 . ( the connectives of S2 . i) & the ResultSort of S1 . ( the connectives of S1 . i) = the ResultSort of S2 . ( the connectives of S2 . i) ) ) & S1 is bool-correct holds
S2 is bool-correct