Index: /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/Trie.java
===================================================================
--- /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/Trie.java	(revision 250)
+++ /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/Trie.java	(revision 251)
@@ -85,4 +85,7 @@
 	 */
 	public void train(List<T> sequence, int maxOrder) {
+		if( maxOrder<1 ) {
+			return;
+		}
 		IncompleteMemory<T> latestActions = new IncompleteMemory<T>(maxOrder);
 		int i = 0;
Index: /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/TrieNode.java
===================================================================
--- /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/TrieNode.java	(revision 250)
+++ /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/TrieNode.java	(revision 251)
@@ -246,5 +246,5 @@
 	void getGraph(TrieVertex parent, DelegateTree<TrieVertex, Edge> graph) {
 		TrieVertex currentVertex;
-		if (symbol == null) {
+		if (isRoot()) {
 			currentVertex = new TrieVertex("root");
 			graph.addVertex(currentVertex);
@@ -270,5 +270,5 @@
 	void appendDotRepresentation(StringBuilder stringBuilder) {
 		String thisSaneId;
-		if (symbol == null) {
+		if (isRoot()) {
 			thisSaneId = "root";
 		} else {
@@ -297,4 +297,15 @@
 	protected boolean isLeaf() {
 		return children.isEmpty();
+	}
+	
+	/**
+	 * <p>
+	 * Checks if the node is the root.
+	 * </p>
+	 * 
+	 * @return true if the node is the root of the trie, false otherwise
+	 */
+	protected boolean isRoot() {
+		return symbol==null;
 	}