diff --git a/src/main/java/exceptions/SyntaxException.java b/src/main/java/exceptions/SyntaxException.java
new file mode 100644
index 0000000..c93db96
--- /dev/null
+++ b/src/main/java/exceptions/SyntaxException.java
@@ -0,0 +1,13 @@
+package exceptions;
+
+public class SyntaxException extends RuntimeException{
+
+	public SyntaxException() {
+		super("syntax error");
+	}
+	
+	public SyntaxException(String msg) {
+		super(msg);
+	}
+	
+}
diff --git a/src/main/java/models/terms/Dependency.java b/src/main/java/models/terms/Dependency.java
index 8edefba..6783130 100644
--- a/src/main/java/models/terms/Dependency.java
+++ b/src/main/java/models/terms/Dependency.java
@@ -1,10 +1,11 @@
 package models.terms;
 
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.stream.Collectors;
 
+import exceptions.SyntaxException;
 import lombok.Getter;
 import models.algebra.Symbol;
 
@@ -12,65 +13,23 @@
 public class Dependency extends RDLTerm{
 	
 	private RDLTerm dependingTerm;
-	private List<EvaluatableTerm> dependedTerms;
-	private Dependency dependency;
-	private boolean isListType;
+	private Set<EvaluatableTerm> dependedTerms;
 	
-//	public Dependency(RDLTerm dependingTerm, Resource dependedVariable) {
-//		super(new Symbol(":", 2), dependedVariable.getOrder(), dependingTerm.getSize() + dependedVariable.getSize());
-//		this.dependingTerm = dependingTerm;
-//		this.dependedVariable = dependedVariable;
-//		this.dependency = null;
-//		this.addChild(dependingTerm);
-//		this.addChild(dependedVariable);
-//		this.isListType = false;
-//	}
-	
-	public Dependency(RDLTerm dependingTerm, List<EvaluatableTerm> dependedTerms) {
-		super(new Symbol(":", dependedTerms.size() + 1), dependedTerms.get(0).getOrder(), dependingTerm.getSize() + dependedTerms.stream().mapToInt(v -> v.size).sum());
+	public Dependency(RDLTerm dependingTerm, Set<EvaluatableTerm> dependedTerms) {
+		super(new Symbol(":", dependedTerms.size() + 1), dependedTerms.iterator().next().getOrder(), dependingTerm.getSize() + dependedTerms.stream().mapToInt(v -> v.size).sum());
 		this.dependingTerm = dependingTerm;
 		this.dependedTerms = dependedTerms;
-		this.dependency = null;
 		this.addChild(dependingTerm);
-		for (EvaluatableTerm dependedResource: dependedTerms) {
-			this.addChild(dependedResource);
+		for (EvaluatableTerm dependedTerm: dependedTerms) {
+			this.addChild(dependedTerm);
+			if (dependedTerm.getOrder() != getOrder()) {
+				throw new SyntaxException(dependedTerm + " order is not " + getOrder());
+			}
 		}
-		this.isListType = false;
 	}
 	
-	public Dependency(RDLTerm dependingTerm, Resource ...dependedResources) {
-		this(dependingTerm, Arrays.asList(dependedResources));
-	}
-	
-	public Dependency(Dependency dependency) {
-		super(new Symbol(":", 1), dependency.getOrder() - 1, dependency.getSize());
-		this.dependency = dependency;
-		this.dependingTerm = null;
-		this.dependedTerms = null;
-		this.addChild(dependency);
-		this.isListType = true;
-	}
-	
-//	public Dependency(RDLTerm dependingTerm, Resource dependedVariable, int order) {
-//		super(new Symbol(":", order == dependedVariable.order ? 2 : 1), order, dependingTerm.getSize() + dependedVariable.getSize());
-//		if(order == dependedVariable.order) {
-//			this.dependingTerm = dependingTerm;
-//			this.dependedResources = dependedVariable;
-//			this.addChild(dependingTerm);
-//			this.addChild(dependedVariable);
-//			this.dependency = null;
-//			this.isListType = false;
-//		} else {
-//			this.dependency = new Dependency(dependingTerm, dependedVariable, order+1);
-//			this.dependingTerm = null;
-//			this.dependedResources = null;
-//			this.addChild(dependency);
-//			this.isListType = true;
-//		}
-//	}
-	
-	public Dependency getDependency() {
-		return this.dependency;
+	public Dependency(RDLTerm dependingTerm, EvaluatableTerm ...dependedTerms) {
+		this(dependingTerm, new HashSet<>(Arrays.asList(dependedTerms)));
 	}
 	
 	@Override
@@ -85,30 +44,18 @@
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
-		if(dependency == null) {
-			sb.append(dependingTerm.toTermString());
-			sb.append(" : ");
-			sb.append(dependedTerms.toString());
-		} else {
-			sb.append('[');
-			sb.append(dependency.toString());
-			sb.append(']');
-		}
+		sb.append(dependingTerm.toTermString());
+		sb.append(" : ");
+		sb.append(dependedTerms.toString());
 		return sb.toString();
 	}
 	
 	@Override
 	public String toStringWithOrder() {
 		StringBuilder sb = new StringBuilder();
-		if(dependency == null) {
-			sb.append(dependingTerm.toStringWithOrder());
-			sb.append(" : ");
-			sb.append(dependedTerms.stream().map(RDLTerm::toStringWithOrder).collect(Collectors.joining(", ")));
-		} else {
-			sb.append('[');
-			sb.append(dependency.toStringWithOrder());
-			sb.append(']');
-		}
+		sb.append(dependingTerm.toStringWithOrder());
+		sb.append(" : ");
+		sb.append(dependedTerms.stream().map(RDLTerm::toStringWithOrder).collect(Collectors.joining(", ")));
 		return sb.toString() + "(" + order + ")";
 	}
 	
@@ -123,12 +70,6 @@
 			return false;
 		}
 		Dependency anotherDep = (Dependency) another;
-		if(anotherDep.isListType() != isListType()) {
-			return false;
-		}
-		if(isListType()) {
-			return anotherDep.getDependency().equals(dependency);
-		}
 		return anotherDep.getDependingTerm().equals(dependingTerm)
 				&& anotherDep.getDependedTerms().equals(dependedTerms);
 	}
@@ -140,7 +81,7 @@
 	
 	@Override
 	public Object clone() {
-		return new Dependency((RDLTerm) dependingTerm.clone(), new ArrayList<>(dependedTerms));
+		return new Dependency((RDLTerm) dependingTerm.clone(), new HashSet<>(dependedTerms));
 	}
 
 }
diff --git a/src/main/java/models/terms/SetEvaluatableTerm.java b/src/main/java/models/terms/SetEvaluatableTerm.java
deleted file mode 100644
index 05fc8e2..0000000
--- a/src/main/java/models/terms/SetEvaluatableTerm.java
+++ /dev/null
@@ -1,86 +0,0 @@
-package models.terms;
-
-import lombok.Getter;
-import models.algebra.Symbol;
-
-@Getter
-public class SetEvaluatableTerm extends EvaluatableTerm{
-
-	private EvaluatableTerm term;
-	
-	public SetEvaluatableTerm(EvaluatableTerm term) {
-		super(new Symbol("", 1), term.getOrder() - 1, term.getSize());
-		this.term = term;
-		this.addChild(term);
-	}
-	
-	public SetEvaluatableTerm(EvaluatableTerm term, int order) {
-		super(new Symbol("", 1), order, term.getSize());
-		if(term.getOrder() > order + 1) {
-			var childTerm = new SetEvaluatableTerm(term, order+1); 
-			this.term = childTerm;
-			this.addChild(childTerm);
-		} else {
-			this.term = term;
-			this.addChild(term);
-		}
-	}
-	
-	public void setTerm(EvaluatableTerm newTerm) {
-		setChild(0, newTerm);
-		this.term = newTerm;
-	}
-	
-	@Override
-	public EvaluatableTerm linearRightNormalize() {
-		return (SetEvaluatableTerm) clone();
-	}
-
-	@Override
-	public void selfLinearRightNormalize() {
-	}
-	
-	@Override
-	public boolean isLinearRightNormalized() {
-		return term.isLinearRightNormalized();
-	}
-
-	
-	@Override
-	public boolean equals(Object another) {
-		if(! (another instanceof SetEvaluatableTerm)) {
-			return false;
-		}
-		var term = (SetEvaluatableTerm) another;
-		return term.getTerm().equals(getTerm());
-	}
-
-	@Override
-	public int hashCode() {
-		return ("SET" + toString()).hashCode();
-	}
-	
-	@Override
-	public String toString() {
-		StringBuilder sb = new StringBuilder();
-		sb.append('{');
-		sb.append(term.toString());
-		sb.append('}');
-		return sb.toString();
-	}
-	
-	@Override
-	public String toStringWithOrder() {
-		StringBuilder sb = new StringBuilder();
-		sb.append('{');
-		sb.append(term.toStringWithOrder());
-		sb.append('}');
-		return sb.toString() + "(" + order + ")";
-	}
-
-	@Override
-	public Object clone() {
-		return new SetEvaluatableTerm((EvaluatableTerm) term.clone(), order);
-	}
-
-}