diff --git a/mlpp/lin_alg/mlpp_vector.h b/mlpp/lin_alg/mlpp_vector.h
index e5c9ef6..4c7b3ae 100644
--- a/mlpp/lin_alg/mlpp_vector.h
+++ b/mlpp/lin_alg/mlpp_vector.h
@@ -327,6 +327,11 @@ public:
 		return true;
 	}
 
+	// New apis should look like this:
+	//Ref<MLPPVector> substract(const Ref<MLPPVector> &b);
+	//void substracted(const Ref<MLPPVector> &b);
+	//void subtraction(const Ref<MLPPVector> &a, const Ref<MLPPVector> &b); -> result is in this (subtractionv like)
+
 	Ref<MLPPVector> flattenmnv(const Vector<Ref<MLPPVector>> &A);
 
 	Ref<MLPPVector> hadamard_productnv(const Ref<MLPPVector> &a, const Ref<MLPPVector> &b);