Killing the $GCH$ everywhere with a single real

Abstract

Shelah—Woodin [10] investigate the possibility of violating instances of GCH through the addition of a single real. In particular they show that it is possible to obtain a failure of CH by adding a single real to a model of GCH, preserving cofinalities. In this article we strengthen their result by showing that it is possible to violate GCH at all infinite cardinals by adding a single real to a model of GCH. Our assumption is the existence of an $H(\kappa^{+3})$-strong cardinal; by work of Gitik and Mitchell [6] it is known that more than an $H(\kappa^{++})$-strong cardinal is required.