diff --git a/src/TNL/Experimental/Arithmetics/MultiPrecision.cpp b/src/TNL/Experimental/Arithmetics/MultiPrecision.cpp
index fbe325e8ace2e17792960248c7943d2371718748..efb1286015f68b882f51e055ea2ad4dcada23082 100644
--- a/src/TNL/Experimental/Arithmetics/MultiPrecision.cpp
+++ b/src/TNL/Experimental/Arithmetics/MultiPrecision.cpp
@@ -9,6 +9,8 @@
 
 #include "MultiPrecision.h"
 
+namespace TNL {
+
 /* CONSTRUCTORS */
 
 MultiPrecision::MultiPrecision(){
@@ -145,4 +147,6 @@ void MultiPrecision::printMP(){
 MultiPrecision::~MultiPrecision(){
 }
 
+} // namespace TNL
+
 #endif
\ No newline at end of file
diff --git a/src/TNL/Experimental/Arithmetics/MultiPrecision.h b/src/TNL/Experimental/Arithmetics/MultiPrecision.h
index 858bf3a5fa94214b505bfbf86ba9752437b742be..3cf5fbce737c17dfb45807a63f8cc9af19259d6e 100644
--- a/src/TNL/Experimental/Arithmetics/MultiPrecision.h
+++ b/src/TNL/Experimental/Arithmetics/MultiPrecision.h
@@ -9,11 +9,11 @@
 /* Source: https://gmplib.org/ */
 
 #ifdef HAVE_GMP
-
 #include <gmp.h>
-
 #endif
 
+namespace TNL {
+
 class MultiPrecision{
 public:
     /* NUMBER */
@@ -57,4 +57,6 @@ public:
 
     /* DESTRUCTOR */
     ~MultiPrecision();
-};
\ No newline at end of file
+};
+
+} // namespace TNL
\ No newline at end of file
diff --git a/src/TNL/Experimental/Arithmetics/Quad.h b/src/TNL/Experimental/Arithmetics/Quad.h
index fa321553551a6c92b901cdc362cb5099d12635d4..524b857e0a83fad13e5b95c7d88e028cc111e832 100644
--- a/src/TNL/Experimental/Arithmetics/Quad.h
+++ b/src/TNL/Experimental/Arithmetics/Quad.h
@@ -10,6 +10,8 @@
  *        Quad edited to use templates.
  */
 
+namespace TNL {
+
 template <class T>
 class Quad
 {
@@ -102,3 +104,4 @@ void zeroQuad(T *a); // Reset quad-double
 template <typename T>
 void printQuad(T *a); // Print of quad-double
 
+} //namespace TNL
diff --git a/src/TNL/Experimental/Arithmetics/Quad_impl.h b/src/TNL/Experimental/Arithmetics/Quad_impl.h
index 393a0427089dba473b5d70a8b061165e140b1109..5ba054f739db3d31f005e891612a0c40cdc16057 100644
--- a/src/TNL/Experimental/Arithmetics/Quad_impl.h
+++ b/src/TNL/Experimental/Arithmetics/Quad_impl.h
@@ -15,6 +15,7 @@
 
 #define ABS(n) ((n) > 0 ? (n): -(n))
 
+namespace TNL {
 
 template <class T>
 Quad<T>::Quad() {
@@ -625,3 +626,5 @@ template <typename T>
 void printQuad(T *a) {
     printf("%.15le + %.15le + %.15le + %.15le\n", a[0], a[1], a[2], a[3]);
 }
+
+} // namespace TNL
\ No newline at end of file
diff --git a/src/TNL/Experimental/Arithmetics/UnitTests/.MultiPrecisionTest.cpp.swp b/src/TNL/Experimental/Arithmetics/UnitTests/.MultiPrecisionTest.cpp.swp
new file mode 100644
index 0000000000000000000000000000000000000000..da4d7b79f9b8c5cf7f57b3be25a155cd54a2cf54
Binary files /dev/null and b/src/TNL/Experimental/Arithmetics/UnitTests/.MultiPrecisionTest.cpp.swp differ
diff --git a/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp b/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp
index 5b3a7743d6ba8bce6de42fcd34d33a9e0cc91630..2fc44ed1c4aec563a2d00d25c3315d8a4e34eeb1 100644
--- a/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp
+++ b/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp
@@ -15,6 +15,7 @@
 
 #include <TNL/Experimental/Arithmetics/MultiPrecision.h>
 
+using namespace TNL;
 
 #ifdef HAVE_GTEST 
 TEST( MultiPrecisionTest, test_1 )
diff --git a/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp.save b/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp.save
new file mode 100644
index 0000000000000000000000000000000000000000..14623511ee063313c4df33b0afc2f9a7c7d5c026
--- /dev/null
+++ b/src/TNL/Experimental/Arithmetics/UnitTests/MultiPrecisionTest.cpp.save
@@ -0,0 +1,4 @@
+int main (void) {
+return 0;
+
+}
diff --git a/src/TNL/Experimental/Arithmetics/UnitTests/QuadTest.cpp b/src/TNL/Experimental/Arithmetics/UnitTests/QuadTest.cpp
index 046be65f7f036a05d63292802f1d8e89591ae66c..a15dbc0998492d2d6478cb091a8aa74274e0036a 100644
--- a/src/TNL/Experimental/Arithmetics/UnitTests/QuadTest.cpp
+++ b/src/TNL/Experimental/Arithmetics/UnitTests/QuadTest.cpp
@@ -12,6 +12,7 @@
 #include <TNL/Experimental/Arithmetics/MultiPrecision.h>
 #include <TNL/Experimental/Arithmetics/Quad.h>
 
+using namespace TNL;
 
 #ifdef HAVE_GTEST 
 TEST( QuadTest, test_1 )
diff --git a/src/TNL/Experimental/Arithmetics/UnitTests/test b/src/TNL/Experimental/Arithmetics/UnitTests/test
new file mode 100644
index 0000000000000000000000000000000000000000..2bae88110fbc187e86738178f72b957e7ac0beb6
Binary files /dev/null and b/src/TNL/Experimental/Arithmetics/UnitTests/test differ