On ultrapowers of Banach spaces of type ${\mathcal{L}}_{\infty }$

Antonio Avilés, Félix Cabello Sánchez, Jesús M. F. Castillo +2

We prove that no ultraproduct of Banach spaces via a countably incomplete ultrafilter can contain $c_0$ complemented. This shows that a "result" widely used in the theory of ultrap…