diff --git a/src/math/lp/nla_grobner.cpp b/src/math/lp/nla_grobner.cpp
index 7c75ed0b8..0975b19a8 100644
--- a/src/math/lp/nla_grobner.cpp
+++ b/src/math/lp/nla_grobner.cpp
@@ -475,9 +475,9 @@ nla_grobner::equation * nla_grobner::simplify(equation const * source, equation
 }
 
 std::ostream& nla_grobner::display_equation(std::ostream & out, equation & eq) {
-    tout << "m_exp = " << *eq.m_exp << "\n";
-    tout << "dep = "; display_dependency(tout, eq.m_dep) << "\n";
-    return tout;
+    out << "m_exp = " << *eq.m_exp << "\n";
+    out << "dep = "; display_dependency(out, eq.m_dep) << "\n";
+    return out;
 }
 
 void nla_grobner::display_monomial(std::ostream & out, monomial const & m) const {