(formula, solver_name=None, logic=None, portfolio=None)
return env.factory.is_valid(formula,
                                solver_name=solver_name,
                                logic=logic,
                                portfolio=portfolio)
Similar to :py:func:`is_sat` but checks validity.

    :param formula: The target formula
    :type  formula: FNode
    :param solver_name: Specify the name of the solver to be used
    :param logic: Specify the logic that is going to be used
    :param portfolio: A list of solver names to perform portfolio solving.
    :returns: Whether the formula is SAT or UNSAT but checks validity
    :rtype: bool
Similar to :py:func:`is_sat` but checks validity.
Similar to : py : func : is_sat but checks validity .
def is_valid(formula, solver_name=None, logic=None, portfolio=None):
    """Similar to :py:func:`is_sat` but checks validity.

    :param formula: The target formula
    :type  formula: FNode
    :param solver_name: Specify the name of the solver to be used
    :param logic: Specify the logic that is going to be used
    :param portfolio: A list of solver names to perform portfolio solving.
    :returns: Whether the formula is SAT or UNSAT but checks validity
    :rtype: bool
    """
    env = get_env()
    if formula not in env.formula_manager:
        warnings.warn("Warning: Contextualizing formula during is_valid")
        formula = env.formula_manager.normalize(formula)

    return env.factory.is_valid(formula,
                                solver_name=solver_name,
                                logic=logic,
                                portfolio=portfolio)
def is_valid ( formula , solver_name = None , logic = None , portfolio = None ) : env = get_env ( ) if formula not in env . formula_manager : warnings . warn ( "Warning: Contextualizing formula during is_valid" ) formula = env . formula_manager . normalize ( formula ) return env . factory . is_valid ( formula , solver_name = solver_name , logic = logic , portfolio = portfolio )