lt="Upper Crystal Springs Reservoir, near Belmont, CA" />
<figcaption aria-hidden="true">Upper Crystal Springs Reservoir, near Belmont, CA</figcaption>
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  \frac{\quad}{\Delta \, \Gamma , x \, : \, \tau \vdash x \, : \, \tau} \;
  (16.2a)
  \quad \frac{\Delta \vdash \tau_1 \, \textsf{type} \quad \Delta \, \Gamma , x \, : \, \tau_1 \vdash e \, : \, \tau_2}{\Delta \, \Gamma \vdash \texttt{lam}\{\tau_1\}(x.e) \, : \, \texttt{arr}(\tau_