Index: branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/IFragment.cs
===================================================================
--- branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/IFragment.cs	(revision 9835)
+++ branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/IFragment.cs	(revision 9835)
@@ -0,0 +1,30 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2013 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+using HeuristicLab.Core;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  public interface IFragment : IItem {
+    ISymbolicExpressionTreeNode Root { get; set; }
+    int Length { get; set; }
+    int Index { get; set; }
+    int OldIndex { get; set; }
+  }
+}
Index: branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeComparer.cs
===================================================================
--- branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeComparer.cs	(revision 9835)
+++ branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeComparer.cs	(revision 9835)
@@ -0,0 +1,7 @@
+﻿using System.Collections.Generic;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  public interface ISymbolicExpressionTreeNodeComparer : IComparer<ISymbolicExpressionTreeNode> {
+
+  }
+}
Index: branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeSimilarityComparer.cs
===================================================================
--- branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeSimilarityComparer.cs	(revision 9835)
+++ branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/ISymbolicExpressionTreeNodeSimilarityComparer.cs	(revision 9835)
@@ -0,0 +1,10 @@
+﻿using System.Collections.Generic;
+using HeuristicLab.Core;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  public interface ISymbolicExpressionTreeNodeSimilarityComparer : IEqualityComparer<ISymbolicExpressionTreeNode>, IItem {
+    bool MatchConstantValues { get; set; }
+    bool MatchVariableWeights { get; set; }
+    bool MatchVariableNames { get; set; }
+  }
+}
Index: branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/Operators/ITracingSymbolicExpressionTreeOperator.cs
===================================================================
--- branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/Operators/ITracingSymbolicExpressionTreeOperator.cs	(revision 9835)
+++ branches/HeuristicLab.EvolutionaryTracking/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Interfaces/Operators/ITracingSymbolicExpressionTreeOperator.cs	(revision 9835)
@@ -0,0 +1,31 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using HeuristicLab.Parameters;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  /// <summary>
+  /// Interface for operators that can be applied to symbolic expression trees.
+  /// </summary>
+  public interface ITracingSymbolicExpressionTreeOperator : ISymbolicExpressionTreeOperator {
+    ValueParameter<ISymbolicExpressionTreeNodeSimilarityComparer> SymbolicExpressionTreeNodeComparerParameter { get; }
+  }
+}
