[bibtex key=DzamonjaHamkins2006:DiamondCanFail]

If $\kappa$ is any strongly unfoldable cardinal, then this is preserved in a forcing extension in which ${◊}_{\kappa }(\text{REG})$ fails. This result continues the progression of the corresponding results for weakly compact cardinals, due to Woodin, and for indescribable cardinals, due to Hauser.