Nontrivial automorphisms of $\mathcal{P}(\omega )/\mathrm{Fin}$ in Cohen models

Will Brian, Alan Dow

We show that if $\kappa <{\aleph }_{\omega }$ Cohen reals are added to a model of $\mathsf{CH}$, then there are nontrivial automorphisms of $\mathcal{P}(\omega )/\mathrm{Fin}$ in the extension. Under som…