diff --git a/iii/forcing/03_forcing.tex b/iii/forcing/03_forcing.tex
index 112964b..046c28d 100644
--- a/iii/forcing/03_forcing.tex
+++ b/iii/forcing/03_forcing.tex
@@ -374,7 +374,7 @@ \subsection{Pairing}
 We can define unordered and ordered pairs of names, with sensible interpretations.
 \begin{definition}
     Given \( \mathbb P \)-names \( \dot x, \dot y \), let
-    \[ \operatorname{up}(\dot x, \dot y) = \qty{\langle \Bbbone, \dot x \rangle, \langle Bbbone, \dot y \rangle} \]
+    \[ \operatorname{up}(\dot x, \dot y) = \qty{\langle \Bbbone, \dot x \rangle, \langle \Bbbone, \dot y \rangle} \]
     and
     \[ \operatorname{op}(\dot x, \dot y) = \operatorname{up}(\operatorname{up}(\dot x, \dot x), \operatorname{up}(\dot x, \dot y)) \]
 \end{definition}