diff --git a/source/exec.tex b/source/exec.tex
index b9d739c0b8..9a2cf70cd7 100644
--- a/source/exec.tex
+++ b/source/exec.tex
@@ -2583,7 +2583,7 @@
 \end{itemize}
 
 Otherwise, it is expression-equivalent to
-\tcode{\exposid{make-sender}(\exposid{just-cpo}, \exposid{product-type}{ts...})}.
+\tcode{\exposid{make-sender}(\exposid{just-cpo}, \exposid{product-type}\{ts...\})}.
 
 For \tcode{just}, \tcode{just_error}, and \tcode{just_stopped},
 let \exposid{set-cpo} be