diff --git a/core/src/main/java/it/cavallium/warppi/math/FunctionVisitor.java b/core/src/main/java/it/cavallium/warppi/math/FunctionVisitor.java
index 48697534..148535c6 100644
--- a/core/src/main/java/it/cavallium/warppi/math/FunctionVisitor.java
+++ b/core/src/main/java/it/cavallium/warppi/math/FunctionVisitor.java
@@ -18,7 +18,6 @@ public interface FunctionVisitor<T> {
 	T visit(ArcTangent arcTangent);
 	T visit(Cosine cosine);
 	T visit(Division division);
-	T visit(EmptyNumber emptyNumber);
 	T visit(Equation equation);
 	T visit(EquationsSystem equationsSystem);
 	T visit(EquationsSystemPart equationsSystemPart);
diff --git a/core/src/main/java/it/cavallium/warppi/math/rules/dsl/VisitorPattern.java b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/VisitorPattern.java
index 8ed69a81..3532d5b3 100644
--- a/core/src/main/java/it/cavallium/warppi/math/rules/dsl/VisitorPattern.java
+++ b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/VisitorPattern.java
@@ -46,11 +46,6 @@ public abstract class VisitorPattern implements Pattern, FunctionVisitor<Optiona
 		return Optional.empty();
 	}
 
-	@Override
-	public Optional<Map<String, Function>> visit(final EmptyNumber emptyNumber) {
-		return Optional.empty();
-	}
-
 	@Override
 	public Optional<Map<String, Function>> visit(final Equation equation) {
 		return Optional.empty();