A rigidity theorem for $\ddot{I}{€}_{\ast }$-étale ${\mathbb{E}}_k$-algebras

Xiansheng Li

We prove a rigidity theorem for $\ddot{I}{€}_{\ast }$-étale ${\mathbb{E}}_k$-algebras over an ${\mathbb{E}}_{k+1}$-ring spectrum: the category of $\ddot{I}{€}_{\ast }$-étale extensions of an ${\mathbb{E}}_k$-algebra i…