diff --git a/source/numerics.tex b/source/numerics.tex
index 5f2e55b4c7..b09eeaa57b 100644
--- a/source/numerics.tex
+++ b/source/numerics.tex
@@ -10467,6 +10467,7 @@
 
 \rSec2[linalg.syn]{Header \tcode{<linalg>} synopsis}
 
+\indexheader{linalg}%
 \begin{codeblock}
 namespace std::linalg {
   // \ref{linalg.tags.order}, storage order tags