def strictly_stronger(S,T):
"""Returns True if every formula in S entails the corresponding formula in T."""
for node in S:
s_formula = S.formula_conj(node)
t_formula = T.formula_conj(node)
if not entails(t_formula, [s_formula]):
return False
return True
def test_entails():
A, B, C = symbols('A, B, C')
assert entails(A, [A >> B, ~B]) is False
assert entails(B, [Equivalent(A, B), A]) is True
assert entails((A >> B) >> (~A >> ~B)) is False
assert entails((A >> B) >> (~B >> ~A)) is True
def test_entails():
A, B, C = symbols('A, B, C')
assert entails(A, [A >> B, ~B]) is False
assert entails(B, [Equivalent(A, B), A]) is True
assert entails((A >> B) >> (~A >> ~B)) is False
assert entails((A >> B) >> (~B >> ~A)) is True