diff --git a/test/test6/test6.hpp b/test/test6/test6.hpp
index bb67ef32..0097ac14 100644
--- a/test/test6/test6.hpp
+++ b/test/test6/test6.hpp
@@ -22,7 +22,6 @@
 #include <boost/numeric/ublas/vector.hpp>
 #include <boost/numeric/ublas/matrix.hpp>
 #include <boost/numeric/ublas/matrix_proxy.hpp>
-#include <boost/numeric/ublas/triangular.hpp>
 #include <boost/numeric/ublas/symmetric.hpp>
 #include <boost/numeric/ublas/io.hpp>