f1==(not a or not b) and c: ((not a) and c) or ((not b) and c)
f2==not ((true or a) and (not not false and b or c)): ((((not true) and (not true)) and (not a)) and (not a)) or ((((not true) and (not true)) and (not a)) and (not c)) or ((((not true) and (not true)) and (not (not (not false)))) and (not a)) or ((((not true) and (not true)) and (not (not (not false)))) and (not c)) or ((((not true) and (not true)) and (not b)) and (not a)) or ((((not true) and (not true)) and (not b)) and (not c)) or ((((not true) and (not c)) and (not a)) and (not a)) or ((((not true) and (not c)) and (not a)) and (not c)) or ((((not true) and (not c)) and (not (not (not false)))) and (not a)) or ((((not true) and (not c)) and (not (not (not false)))) and (not c)) or ((((not true) and (not c)) and (not b)) and (not a)) or ((((not true) and (not c)) and (not b)) and (not c)) or ((((not (not (not false))) and (not true)) and (not a)) and (not a)) or ((((not (not (not false))) and (not true)) and (not a)) and (not c)) or ((((not (not (not false))) and (not true)) and (not (not (not false)))) and (not a)) or ((((not (not (not false))) and (not true)) and (not (not (not false)))) and (not c)) or ((((not (not (not false))) and (not true)) and (not b)) and (not a)) or ((((not (not (not false))) and (not true)) and (not b)) and (not c)) or ((((not (not (not false))) and (not c)) and (not a)) and (not a)) or ((((not (not (not false))) and (not c)) and (not a)) and (not c)) or ((((not (not (not false))) and (not c)) and (not (not (not false)))) and (not a)) or ((((not (not (not false))) and (not c)) and (not (not (not false)))) and (not c)) or ((((not (not (not false))) and (not c)) and (not b)) and (not a)) or ((((not (not (not false))) and (not c)) and (not b)) and (not c)) or ((((not b) and (not true)) and (not a)) and (not a)) or ((((not b) and (not true)) and (not a)) and (not c)) or ((((not b) and (not true)) and (not (not (not false)))) and (not a)) or ((((not b) and (not true)) and (not (not (not false)))) and (not c)) or ((((not b) and (not true)) and (not b)) and (not a)) or ((((not b) and (not true)) and (not b)) and (not c)) or ((((not b) and (not c)) and (not a)) and (not a)) or ((((not b) and (not c)) and (not a)) and (not c)) or ((((not b) and (not c)) and (not (not (not false)))) and (not a)) or ((((not b) and (not c)) and (not (not (not false)))) and (not c)) or ((((not b) and (not c)) and (not b)) and (not a)) or ((((not b) and (not c)) and (not b)) and (not c))
f3==not (a or not a) implies false: (not (not a)) or (not (not (not a))) or false
f4==true implies false: (not true) or false
f5==not f4: ((not (not true)) and (not false))
f6==a and not false or b: (a and (not false)) or b
f6b==a and not false or b: (a and (not false)) or b
f1 = f1: true
f2 = f2: true
f1 = f2: false
f2 = f1: false
f6 = f6b: true
f1["a": true, "b": false, "c": true]: true
f2["a": true, "b": false, "c": true]: false
f3["a": true, "b": false, "c": true]: true
f4["a": true, "b": false, "c": true]: false
f5["a": true, "b": false, "c": true]: true
f6["a": true, "b": false, "c": true]: true
f1's vars: a c b c 
f2's vars: a a a c a c b a b c c a a c a c c a c c c b a c b c a a a c a c b a b c c a a c a c c a c c c b a c b c b a a b a c b a b c b b a b b c b c a a b c a c b c a b c c b c b a b c b c 
f3's vars: a a 
f4's vars: 
f5's vars: 
f6's vars: a b 
f1 is tautology: false
f2 is tautology: false
f3 is tautology: true
f4 is tautology: false
f5 is tautology: true
f6 is tautology: false