The Special Aronszajn Tree Property at $\kappa^+$ and $\square_{\kappa, 2}$

Abstract

We show that for any regular cardinal $\kappa$, $\square_{\kappa, 2}$ is consistent with "all $\kappa^+$-Aronszajn trees are special." By a result of Shelah and Stanley this is optimal in the sense that $\square_{\kappa, 2}$ may not be strengthened to $\square_{\kappa}$. Using methods of Golshani and Hayut we obtain our consistency result simultaneously for all regular $\kappa$.