 Let \(\bbN^+\) be the natural numbers without 0. Below we shall assume that \(\Omega_n\) \((n\in\bbN^+)\) is a “large” ordinal and that \(\omega&lt;\Omega_n &lt;\Omega_{n+1}\). Their limit, \(\sup_{n\in\bbN^+}\Omega_n\), will be denoted by \(\Omega_{\omega}\).