Review

Theorem 12   $\mathbf{IP[poly]} = \mathbf{PSPACE}$

Proof. $\mathbf{IP}\subseteq \mathbf{PSPACE}$. To show $\mathbf{PSPACE}\subseteq \mathbf{IP}$, we showed an $\mathbf{IP}$ protocol for $\mathsf{TQBF}$.

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