def logical_consequence(formula, premises):
Utils.verified_propositions(formula)
if not isinstance(premises, list):
raise FormulaArgumentError
for index, premise in enumerate(premises):
set_formula = AND(set_formula, premise) if index else premises[0]
return not satisfiability_checking(AND(set_formula, NOT(formula)))
def truth_table_generator(formula, atoms=None):
Utils.verified_propositions(formula)
atoms = get_atoms(formula) if atoms == None else atoms
truth_table = collections.OrderedDict()
num_rows = 2**len(atoms)
count_for_change = [2**(i - 1) for i in range(len(atoms), 0, -1)]
for index, atom in enumerate(atoms):
truth_table[repr(atom)] = (_generate_values_of_atom_(
num_rows, count_for_change[index]))
for formula in get_formulas(formula, atoms):
truth_table[repr(formula)] = (_generate_values_of_formula_(
formula, num_rows, atoms, truth_table))
return truth_table
def get_formulas(formula, atoms):
Utils.verified_propositions(formula)
return list(filter(lambda f: f not in atoms, formula.sub_formula))
def get_atoms(formula):
Utils.verified_propositions(formula)
return sorted(filter(lambda f: isinstance(f, Atom), formula.sub_formula),
key=repr)
def satisfiability_checking(formula):
Utils.verified_propositions(formula)
truth_table = truth_table_generator(formula)
return True in truth_table[repr(formula)]
def get_atoms(formula):
Utils.verified_propositions(formula)
return list(filter(lambda f: isinstance(f, Atom), formula.sub_formula))