Iterated Forcing with $^{\omega} \omega$-bounding and Semiproper Preorders (Axiomatic Set Theory)
Tadatoshi Miyamoto · Institutional Repositories DataBase (IRDB) · 2001
Assume the Continuum Hypothesis (CH) in the ground model.If we iteratively force with preorders which are $\omega\omega$ -bounding and semiproper taking suitable limits, then so is the final preorder constructed.Therefore we may show that the Cofinal Branch Principle (CBP) of [F] is strictly weaker than the Semiproper Forcing Axiom (SPFA).