diff --git a/ibex_NodeType.cpp b/ibex_NodeType.cpp
new file mode 100644
index 000000000..24918e1b0
--- /dev/null
+++ b/ibex_NodeType.cpp
@@ -0,0 +1,310 @@
+//============================================================================
+//                                  I B E X
+// File        : ibex_NodeType.cpp
+// Author      : Gilles Chabert
+// Copyright   : Ecole des Mines de Nantes (France)
+// License     : See the LICENSE file
+// Created     : 18 Aug 2014
+//============================================================================
+
+#include "ibex_NodeType.h"
+
+// =========== shortcuts ==================
+#define IN         __IBEX_IN__
+#define OUT        __IBEX_OUT__
+#define UNK        __IBEX_UNK__
+#define UNK_IN     __IBEX_UNK_IN__
+#define UNK_OUT    __IBEX_UNK_OUT__
+#define UNK_IN_OUT __IBEX_UNK_IN_OUT__
+#define IN_TMP     __IBEX_IN_TMP__
+// ========================================
+
+namespace ibex {
+// relic from irregular set, need for SetBisect constructor
+NodeType operator|(NodeType x, NodeType y) {
+	switch (x) {
+	case IN : {
+		switch(y) {
+		case IN :        return IN;
+		case OUT :
+		case UNK_OUT:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_IN;
+		}
+	}
+	break;
+	case OUT : {
+		switch(y) {
+		case OUT :       return OUT;
+		case IN :
+		case UNK_IN:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_OUT;
+		}
+	}
+	break;
+	case UNK : {
+		switch(y) {
+		case IN :
+		case UNK_IN:  return UNK_IN;
+		case OUT :
+		case UNK_OUT: return UNK_OUT;
+		case UNK:     return UNK;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_IN : {
+		switch(y) {
+		case IN :
+		case UNK_IN:
+		case UNK :    return UNK_IN;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_OUT : {
+		switch(y) {
+		case OUT :
+		case UNK_OUT:
+		case UNK :    return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	default :
+		//Warning: IN_TMP not considered here.
+		return UNK_IN_OUT;
+	}
+}
+
+
+
+// define operator or between two nodetype, assuming the two boxes associated are equal
+NodeType uni(NodeType x,NodeType y) {
+	switch (x) {
+	case IN : {
+		return IN;
+		
+		}
+	break;
+	case OUT : {
+		return y;
+		}
+	break;
+	case UNK : {
+		switch(y) {
+		case IN :     return IN;
+		case UNK_IN:  return UNK_IN;
+		case OUT :    return UNK;
+		case UNK :	  return UNK;
+		case UNK_OUT: return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_IN : {
+		switch(y) {
+		case IN :
+		case UNK_IN:
+		case UNK :    return UNK_IN;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_OUT : {
+		switch(y) {
+		case OUT :
+		case UNK_OUT:
+		case UNK :    return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	default :
+		//Warning: IN_TMP not considered here.
+		return UNK_IN_OUT;
+	}
+
+}
+
+// define operator or between two nodetype, assuming box of nodetype y is subset of box of nodetype x;
+NodeType uni_in(NodeType x, NodeType y) {
+	switch (x) {
+	case IN : {
+		switch(y) {
+		case IN :        return IN;
+		case OUT :		 return IN;
+		case UNK :		 return IN;
+		case UNK_OUT:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_IN;
+		}
+	}
+	break;
+	case OUT : {
+		switch(y) {
+		case OUT :       return OUT;
+		case IN :		 return UNK;
+		case UNK :		 return UNK;
+		case UNK_IN:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_OUT;
+		}
+	}
+	break;
+	case UNK : {
+		switch(y) {
+		return UNK;
+		}
+	}
+	break;
+	/*case UNK_IN : {
+		switch(y) {
+		case IN :
+		case UNK_IN:
+		case UNK :    return UNK_IN;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_OUT : {
+		switch(y) {
+		case OUT :
+		case UNK_OUT:
+		case UNK :    return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;*/
+	default :
+		//Warning: IN_TMP not considered here.
+		return UNK_IN_OUT;
+		
+	}
+}
+
+// define operator and between two nodetype, assuming the two boxes associated are equal
+NodeType inte(NodeType x, NodeType y) {
+	switch (x) {
+	case IN : {
+		return y;
+		}
+	break;
+	case OUT : {
+		return OUT;
+		}
+	break;
+	case UNK : {
+		switch(y) {
+		case IN :     return UNK;
+		case UNK_IN:  return UNK_IN;
+		case OUT :    return OUT;
+		case UNK :	  return UNK;
+		case UNK_OUT: return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_IN : {
+		switch(y) {
+		case IN :
+		case UNK_IN:
+		case UNK :    return UNK_IN;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_OUT : {
+		switch(y) {
+		case OUT :
+		case UNK_OUT:
+		case UNK :    return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	default :
+		//Warning: IN_TMP not considered here.
+		return UNK_IN_OUT;
+	}
+}
+
+
+// define operator and between two nodetype, assuming box of nodetype y is subset of box of nodetype x;
+NodeType inte_in(NodeType x, NodeType y) {
+	switch (x) {
+	case IN : {
+		switch(y) {
+		case IN :        return IN;
+		case OUT :		 return UNK;
+		case UNK :		 return UNK;
+		case UNK_OUT:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_IN;
+		}
+	}
+	break;
+	case OUT : {
+		switch(y) {
+		case OUT :       return OUT;
+		case IN :		 return OUT;
+		case UNK :		 return OUT;
+		case UNK_IN:
+		case UNK_IN_OUT: return UNK_IN_OUT;
+		default :        return UNK_OUT;
+		}
+	}
+	break;
+	case UNK : {
+		switch(y) {
+		case IN :	  return UNK;
+		case UNK_IN:  return UNK_IN;
+		case OUT :	  return UNK;
+		case UNK_OUT: return UNK_OUT;
+		case UNK:     return UNK;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_IN : {
+		switch(y) {
+		case IN :
+		case UNK_IN:
+		case UNK :    return UNK_IN;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	case UNK_OUT : {
+		switch(y) {
+		case OUT :
+		case UNK_OUT:
+		case UNK :    return UNK_OUT;
+		default:      return UNK_IN_OUT;
+		}
+	}
+	break;
+	default :
+		//Warning: IN_TMP not considered here.
+		return UNK_IN_OUT;
+	}
+}
+
+bool certainly_contains_in(NodeType x) {
+	return x==IN || x==UNK_IN || x==UNK_IN_OUT;
+}
+
+bool certainly_contains_out(NodeType x) {
+	return x==OUT || x==UNK_OUT || x==UNK_IN_OUT;
+}
+
+bool possibly_contains_in(NodeType x) {
+	return x!=OUT;
+}
+
+bool possibly_contains_out(NodeType x) {
+	return x!=IN;
+}
+
+} // namespace ibex