(formula)
return get_env().formula_manager.Not(formula)
r""".. math:: \lnot \varphi
r""".. math:: \lnot \varphi
r .. math :: \ lnot \ varphi
def Not(formula):
    r""".. math:: \lnot \varphi"""
    return get_env().formula_manager.Not(formula)
def Not ( formula ) : return get_env ( ) . formula_manager . Not ( formula )