diff --git a/docs/derived.tex b/docs/derived.tex
index 948c5333976d3f5f736ea4bbea92543f2210982f..baac8228731bbeb2a6ffd366b0768d0e285f2ef0 100644
--- a/docs/derived.tex
+++ b/docs/derived.tex
@@ -16,7 +16,7 @@ Now we define:
   \CInv{\gname}{\namesp}{\prop} \eqdef{}& \knowInv\namesp{\prop \lor \ownGhost\gname{1}}
 \end{align*}
 
-It is then straight-forward to prove:
+It is then straight forward to prove:
 \begin{mathpar}
   \inferH{CInv-new}{}
   {\later\prop \vs[\bot] \Exists \gname. \CInvTok\gname{1} * \always\CInv\gname\namesp\prop}