diff -r acd0dc288149 -r 75ed9549d34d src/work/alpar/emptygraph.h
--- a/src/work/alpar/emptygraph.h	Tue Feb 03 13:29:49 2004 +0000
+++ b/src/work/alpar/emptygraph.h	Tue Feb 03 13:41:46 2004 +0000
@@ -30,11 +30,22 @@
   SymEdgeIt &goNext(const SymEdgeIt &);
   EachEdgeIt &goNext(const EachEdgeIt &);
 
-  bool valid(const NodeIt &n);
-  bool valid(const EdgeIt &n);
+  NodeIt head(const EdgeIt &);
+  NodeIt tail(const EdgeIt &);
+  
+  NodeIt aNode(const InEdgeIt &);
+  NodeIt aNode(const OutEdgeIt &);
+  NodeIt aNode(const SymEdgeIt &);
 
-  void setInvalid(const NodeIt &n);
-  void setInvalid(const EdgeIt &n);
+  NodeIt bNode(const InEdgeIt &);
+  NodeIt bNode(const OutEdgeIt &);
+  NodeIt bNode(const SymEdgeIt &);
+
+  bool valid(const NodeIt &);
+  bool valid(const EdgeIt &);
+
+  void setInvalid(const NodeIt &);
+  void setInvalid(const EdgeIt &);
   
   NodeIt addNode();
   EdgeIt addEdge(const NodeIt from,const NodeIt to);