Fix typo

Signed-off-by: zeramorphic <[email protected]>

iii/forcing/01.tex

@@ -579,7 +579,7 @@ \subsection{The reflection theorem}
     Suppose that \( \bigwedge_{i=1}^n \varphi_i \) proves every axiom of \( T \).
     By reflection, \( T \) proves that for every \( \alpha \) there is \( \beta > \alpha \) such that the \( \varphi_i \) hold in \( \mathrm{V}_\beta \) if and only if they hold in \( \mathrm{V} \).
     Since they hold in \( \mathrm{V} \), they must hold in some \( \mathrm{V}_\beta \).
-    Fix \( \beta_0 \) to be the least ordinal such that \( \bigwedge_{i=1}^n \varphi_i^_{\mathrm{V}_{\beta_0}} \).
+    Fix \( \beta_0 \) to be the least ordinal such that \( \bigwedge_{i=1}^n \varphi_i^{\mathrm{V}_{\beta_0}} \).
     Then all of the axioms of \( T \) hold in \( \mathrm{V}_{\beta_0} \), so \( \mathrm{V}_{\beta_0} \vDash T \).
     Since \( T \) extends \( \mathsf{ZF} \), our basic absoluteness results hold, so in particular, if \( \alpha \in \mathrm{V}_{\beta_0} \) then
     \[ \mathrm{V}_\alpha^{\mathrm{V}_{\beta_0}} = \mathrm{V}_\alpha \cap \mathrm{V}_{\beta_0} = \mathrm{V}_\alpha \]