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["c": true, "b": false, "a": true]: true
f2["c": true, "b": false, "a": true]: false
f3["c": true, "b": false, "a": true]: true
f4["c": true, "b": false, "a": true]: false
f5["c": true, "b": false, "a": true]: true
f6["c": true, "b": false, "a": 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