Use a more consistent notation in the bisimulation sketch

sketches.tex

@@ -332,8 +332,8 @@
   \((C, c) \xleftarrow{\outm{1}} (R, r) \xrightarrow{\outm{2}} (D,
   d)\) we can construct a \de{pullback}
   \(\mathsf{Pb}(\outm{1}, \outm{2}) = (P, p)\).  In \(\Set\) this
-  exist necessarily, meaning that the \des{morphism}
-  \((C, c) \xrightarrow{q_1} (P, p) \xleftarrow{p_2} (D, d)\) provide
+  exist necessarily, meaning that the cone \des{morphism}
+  \((C, c) \xrightarrow{p_1} (P, p) \xleftarrow{p_2} (D, d)\) provide
   the intended \defn{beheqiv}{behavioural equivalence}.
 \end{proof}