diff --git a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Combinatorial_map_output_builder.h b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Combinatorial_map_output_builder.h
index a86ab3d1098..a0e6fb11332 100644
--- a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Combinatorial_map_output_builder.h
+++ b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Combinatorial_map_output_builder.h
@@ -458,11 +458,11 @@ private:
       return;
     }
 
-    bool Q_is_between_P1P2 = sorted_around_edge_filtered(indices.first,
-                                                         indices.second,
-                                                         index_p1,index_p2,
-                                                         index_q,P1,P2,Q,
-                                                         nodes,ppmap);
+    bool Q_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,
+                                                              indices.second,
+                                                              index_p1,index_p2,
+                                                              index_q,P1,P2,Q,
+                                                              nodes,ppmap);
 
     if (Q_is_between_P1P2) {
       // poly_first  - poly_second            = took_opposite?P1Q:QP2
@@ -601,8 +601,8 @@ private:
     Vertex_handle Q1=second_hedge->opposite()->next()->vertex();
     // Vertex_handle Q2=second_hedge->next()->vertex();
     bool Q1_is_between_P1P2 =
-      sorted_around_edge_filtered( indices.first, indices.second, index_p1,
-                                   index_p2, index_q1, P1, P2, Q1, nodes, ppmap);
+      OOP::sorted_around_edge_filtered( indices.first, indices.second, index_p1,
+                                        index_p2, index_q1, P1, P2, Q1, nodes, ppmap);
 
 
     //Recover the dart that will be the start point of the different sewing
@@ -1049,13 +1049,13 @@ public:
                        && get(ppmap,P2) !=get(ppmap,Q1) && get(ppmap,P2)!=get(ppmap,Q2));
 
         bool Q1_is_between_P1P2 =
-          sorted_around_edge_filtered( indices.first, indices.second,
-                                       index_p1, index_p2, index_q1,
-                                       P1, P2, Q1, nodes, ppmap);
+          OOP::sorted_around_edge_filtered( indices.first, indices.second,
+                                            index_p1, index_p2, index_q1,
+                                            P1, P2, Q1, nodes, ppmap);
         bool Q2_is_between_P1P2 =
-          sorted_around_edge_filtered( indices.first, indices.second,
-                                       index_p1, index_p2, index_q2,
-                                       P1, P2, Q2, nodes, ppmap);
+          OOP::sorted_around_edge_filtered( indices.first, indices.second,
+                                            index_p1, index_p2, index_q2,
+                                            P1, P2, Q2, nodes, ppmap);
 
         //Recover the dart that will be the start point of the different sewing
         //  dof_X_outside = dart of face of, meaning the triangle containing the
@@ -1074,9 +1074,9 @@ public:
         if ( Q1_is_between_P1P2 ) {
           if( Q2_is_between_P1P2 ) {
             bool P1_is_between_Q1Q2 =
-              sorted_around_edge_filtered(indices.first, indices.second,
-                                          index_q1, index_q2, index_p1,
-                                          Q1, Q2, P1, nodes, ppmap);
+              OOP::sorted_around_edge_filtered(indices.first, indices.second,
+                                               index_q1, index_q2, index_p1,
+                                               Q1, Q2, P1, nodes, ppmap);
             if (!P1_is_between_Q1Q2) {
               // poly_first  - poly_second            = P1Q1 U Q2P2
               // poly_second - poly_first             = {0}
@@ -1160,9 +1160,9 @@ public:
                                 indices, polyline_info); //P2Q1
           } else {
             bool P1_is_between_Q1Q2 =
-              sorted_around_edge_filtered(indices.first, indices.second,
-                                          index_q1,index_q2,index_p1,Q1,Q2,P1,
-                                          nodes,ppmap);
+              OOP::sorted_around_edge_filtered(indices.first, indices.second,
+                                               index_q1,index_q2,index_p1,Q1,Q2,P1,
+                                               nodes,ppmap);
             if (!P1_is_between_Q1Q2) {
               // poly_first  - poly_second            = P1P2
               // poly_second - poly_first             = Q1Q2
diff --git a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
index f75d41ec85d..e258e92e5b9 100644
--- a/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
+++ b/Operations_on_polyhedra/include/CGAL/internal/corefinement/Polyhedra_output_builder.h
@@ -1653,11 +1653,11 @@ public:
       Halfedge_handle second_hedge_opp = second_hedge->opposite();
 
       //vertices from P
-      Vertex_handle P1=first_hedge_opp->next()->vertex();
-      Vertex_handle P2=first_hedge->next()->vertex();
+      // Vertex_handle P1=first_hedge_opp->next()->vertex();
+      // Vertex_handle P2=first_hedge->next()->vertex();
       //vertices from Q
-      Vertex_handle Q1=second_hedge_opp->next()->vertex();
-      Vertex_handle Q2=second_hedge->next()->vertex();
+      // Vertex_handle Q1=second_hedge_opp->next()->vertex();
+      // Vertex_handle Q2=second_hedge->next()->vertex();
 
       int index_p1=node_index_of_incident_vertex(first_hedge_opp->next(),border_halfedges);
       int index_p2=node_index_of_incident_vertex(first_hedge->next(),border_halfedges);
@@ -1896,7 +1896,7 @@ public:
 
             CGAL_assertion( !are_triangles_coplanar_same_side_filtered(indices.first,indices.second,index_p2,index_q2,P2,Q2,nodes) );
 
-            bool Q2_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
+            bool Q2_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
             if ( Q2_is_between_P1P2 ) is_patch_inside_P.set(patch_id_q2); //case 1
             else is_patch_inside_Q.set(patch_id_p2); //case 2
             continue;
@@ -1907,7 +1907,7 @@ public:
               CGAL_assertion( index_p1!=index_p2 || index_p1==-1 );
               coplanar_patches_of_P.set(patch_id_p1);
               coplanar_patches_of_Q.set(patch_id_q2);
-              bool Q1_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
+              bool Q1_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
               if ( Q1_is_between_P1P2 )
               { // case 3
                 is_patch_inside_P.set(patch_id_q1);
@@ -1921,7 +1921,7 @@ public:
               {
                 coplanar_patches_of_P.set(patch_id_p2);
                 coplanar_patches_of_Q.set(patch_id_q1);
-                bool Q2_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
+                bool Q2_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
                 if ( Q2_is_between_P1P2 )
                 {  //case 5
                   is_patch_inside_P.set(patch_id_q2);
@@ -1936,7 +1936,7 @@ public:
                   coplanar_patches_of_Q.set(patch_id_q2);
                   coplanar_patches_of_P_for_union_and_intersection.set(patch_id_p2);
                   coplanar_patches_of_Q_for_union_and_intersection.set(patch_id_q2);
-                  bool Q1_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
+                  bool Q1_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
                   if ( Q1_is_between_P1P2 ) is_patch_inside_P.set(patch_id_q1);  //case 7
                   else is_patch_inside_Q.set(patch_id_p1); //case 8
                   continue;
@@ -1962,15 +1962,15 @@ public:
               ( index_q2 == -1 ? nodes.to_exact(get(ppmap,Q2)): nodes.exact_node(index_q2) )
           );
 
-          bool Q1_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
-          bool Q2_is_between_P1P2 = sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
+          bool Q1_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q1,P1,P2,Q1,nodes,ppmap);
+          bool Q2_is_between_P1P2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_p1,index_p2,index_q2,P1,P2,Q2,nodes,ppmap);
 
           if ( Q1_is_between_P1P2 ){
             is_patch_inside_P.set(patch_id_q1);
             if( Q2_is_between_P1P2 )
             {
               is_patch_inside_P.set(patch_id_q2);
-              bool P1_is_between_Q1Q2 = sorted_around_edge_filtered(indices.first,indices.second,index_q1,index_q2,index_p1,Q1,Q2,P1,nodes,ppmap);
+              bool P1_is_between_Q1Q2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_q1,index_q2,index_p1,Q1,Q2,P1,nodes,ppmap);
               if (!P1_is_between_Q1Q2){
                 // case (a4)
                 // poly_first  - poly_second            = P1Q1 U Q2P2
@@ -2014,7 +2014,7 @@ public:
             }
             else
             {
-              bool P1_is_between_Q1Q2 = sorted_around_edge_filtered(indices.first,indices.second,index_q1,index_q2,index_p1,Q1,Q2,P1,nodes,ppmap);
+              bool P1_is_between_Q1Q2 = OOP::sorted_around_edge_filtered(indices.first,indices.second,index_q1,index_q2,index_p1,Q1,Q2,P1,nodes,ppmap);
               if (!P1_is_between_Q1Q2){
                 //case (e4)
                 // poly_first  - poly_second            = P1P2
diff --git a/Operations_on_polyhedra/include/CGAL/internal/corefinement/predicates.h b/Operations_on_polyhedra/include/CGAL/internal/corefinement/predicates.h
index 98db442039e..b2a5765922d 100644
--- a/Operations_on_polyhedra/include/CGAL/internal/corefinement/predicates.h
+++ b/Operations_on_polyhedra/include/CGAL/internal/corefinement/predicates.h
@@ -25,6 +25,7 @@ namespace CGAL{
 
 namespace Corefinement{
 
+namespace OOP{
 //Considering the plane with normal vector [O_prime,O] and containing O.
 //We define the counterclockwise order around O when looking from
 //the side of the plane into which the vector [O_prime,O] is pointing.
@@ -119,6 +120,8 @@ bool sorted_around_edge_filtered( int O_prime_index,
 
 }
 
-} // end of namespace CGAL::Corefinement
+}
+
+} // end of namespace CGAL::Corefinement::OOP
 
 #endif //CGAL_INTERNAL_COREFINEMENT_PREDICATES_H