diff --git a/LibAutomaton/matrix.c b/LibAutomaton/matrix.c
index 6d4847e..709b0e3 100644
--- a/LibAutomaton/matrix.c
+++ b/LibAutomaton/matrix.c
@@ -342,11 +342,11 @@ Matrix opMatrix(Matrix matrix1,Matrix matrix2,bool (operator)(bool, bool)){
 }
 
 Matrix sumMatrix(Matrix matrix1,Matrix matrix2){
-	opMatrix(matrix1,matrix2,OR);
+	return opMatrix(matrix1,matrix2,OR);
 }
 
 Matrix mulMatrix(Matrix matrix1,Matrix matrix2){
-	opMatrix(matrix1,matrix2,AND);
+	return opMatrix(matrix1,matrix2,AND);
 }
 
 
diff --git a/LibAutomaton/matrix.h b/LibAutomaton/matrix.h
index 58dc71c..389bd4c 100644
--- a/LibAutomaton/matrix.h
+++ b/LibAutomaton/matrix.h
@@ -231,7 +231,7 @@ Matrix andRowSequenceOnMatrix(Matrix m);
 */
 Matrix orRowSequenceOnMatrix(Matrix m);
 Matrix sumMatrix(Matrix matrix1,Matrix matrix2);
-
+Matrix mulMatrix(Matrix matrix1,Matrix matrix2);
 
 #endif