diff --git a/apps/graph/storage_cartesian_function_store.cpp b/apps/graph/storage_cartesian_function_store.cpp
index c9aeee27e..3f5b734e0 100644
--- a/apps/graph/storage_cartesian_function_store.cpp
+++ b/apps/graph/storage_cartesian_function_store.cpp
@@ -5,22 +5,14 @@ extern "C" {
 }
 #include <ion.h>
 
+using namespace Shared;
+
 namespace Graph {
 
-//constexpr const char * StorageCartesianFunctionStore::k_functionNames[k_maxNumberOfFunctions];
-
-Shared::StorageCartesianFunction StorageCartesianFunctionStore::NullModel() {
-  return Shared::StorageCartesianFunction("");
-}
-
 StorageCartesianFunctionStore::StorageCartesianFunctionStore() :
-  Shared::StorageFunctionStore<Shared::StorageCartesianFunction>()
+  Shared::StorageFunctionStore()
 {
-  //addEmptyModel();
-}
-
-char StorageCartesianFunctionStore::symbol() const {
-  return 'x';
+  addEmptyModel();
 }
 
 void StorageCartesianFunctionStore::removeAll() {
@@ -28,5 +20,26 @@ void StorageCartesianFunctionStore::removeAll() {
   addEmptyModel();
 }
 
+void StorageCartesianFunctionStore::addEmptyModel() {
+  Ion::Storage::Record::ErrorStatus error;
+  StorageCartesianFunction newModel = StorageCartesianFunction::NewModel(&error);
+  assert(error == Ion::Storage::Record::ErrorStatus::None);
+}
+
+void StorageCartesianFunctionStore::privateSetMemoizedModelAtIndex(int cacheIndex, Ion::Storage::Record record) const {
+  assert(cacheIndex >= 0 && cacheIndex < k_maxNumberOfMemoizedModels);
+  m_functions[cacheIndex] = StorageCartesianFunction(record);
+}
+
+void StorageCartesianFunctionStore::moveMemoizedModel(int previousIndex, int nextIndex) const {
+  assert(nextIndex >= 0 && nextIndex < k_maxNumberOfMemoizedModels);
+  assert(previousIndex >= 0 && previousIndex < k_maxNumberOfMemoizedModels);
+  m_functions[nextIndex] = m_functions[previousIndex];
+}
+
+StorageExpressionModel * StorageCartesianFunctionStore::memoizedModelAtIndex(int cacheIndex) const {
+  assert(cacheIndex >= 0 && cacheIndex < k_maxNumberOfMemoizedModels);
+  return &m_functions[cacheIndex];
+}
 
 }
diff --git a/apps/graph/storage_cartesian_function_store.h b/apps/graph/storage_cartesian_function_store.h
index 9ee82bb3d..02ca4ae9f 100644
--- a/apps/graph/storage_cartesian_function_store.h
+++ b/apps/graph/storage_cartesian_function_store.h
@@ -8,26 +8,21 @@
 
 namespace Graph {
 
-class StorageCartesianFunctionStore : public Shared::StorageFunctionStore<Shared::StorageCartesianFunction> {
+class StorageCartesianFunctionStore : public Shared::StorageFunctionStore {
 public:
-  static Shared::StorageCartesianFunction NullModel();
-
   StorageCartesianFunctionStore();
-/*  StorageCartesianFunction activeCartesianFunctionAtIndex(int i) override { return (CartesianFunction *)Shared::FunctionStore::activeFunctionAtIndex(i); }
-  StorageCartesianFunction definedFunctionAtIndex(int i) override { return (CartesianFunction *)Shared::FunctionStore::definedFunctionAtIndex(i); }
-*/
-  char symbol() const override;
+  Shared::StorageCartesianFunction * modelAtIndex(int i) const override { return static_cast<Shared::StorageCartesianFunction *>(Shared::StorageFunctionStore::modelAtIndex(i)); }
+  Shared::StorageCartesianFunction * activeFunctionAtIndex(int i) const override { return static_cast<Shared::StorageCartesianFunction *>(Shared::StorageFunctionStore::activeFunctionAtIndex(i)); }
+  Shared::StorageCartesianFunction * definedModelAtIndex(int i) const override { return static_cast<Shared::StorageCartesianFunction *>(Shared::StorageFunctionStore::definedModelAtIndex(i)); }
+  char symbol() const override { return 'x'; }
   void removeAll() override;
-  static constexpr int k_maxNumberOfFunctions = 4; //TODO
 private:
-/*  static constexpr const char * k_functionNames[k_maxNumberOfFunctions] = {
-    "f", "g", "h", "p" //TODO
-  };
-
-  const char * firstAvailableName() override {
-    return firstAvailableAttribute(k_functionNames, FunctionStore::name);
-  }*/
-  const char * firstAvailableName() override { return "f"; }
+  void addEmptyModel();
+  const char * modelExtension() const override { return Shared::GlobalContext::funcExtension; }
+  void privateSetMemoizedModelAtIndex(int cacheIndex, Ion::Storage::Record record) const override;
+  void moveMemoizedModel(int previousIndex, int nextIndex) const override;
+  Shared::StorageExpressionModel * memoizedModelAtIndex(int cacheIndex) const override;
+  mutable Shared::StorageCartesianFunction m_functions[k_maxNumberOfMemoizedModels];
 };
 
 }
diff --git a/apps/shared/storage_expression_model_store.h b/apps/shared/storage_expression_model_store.h
index 26917681e..db157c663 100644
--- a/apps/shared/storage_expression_model_store.h
+++ b/apps/shared/storage_expression_model_store.h
@@ -26,10 +26,11 @@ public:
 
   // Other
   void tidy();
+protected:
+  constexpr static int k_maxNumberOfMemoizedModels = 5;
 private:
   virtual const char * modelExtension() const = 0;
   // Memoization of k_maxNumberOfMemoizedModels consecutive models
-  constexpr static int k_maxNumberOfMemoizedModels = 5;
   mutable int m_firstMemoizedModelIndex;
   mutable uint32_t m_memoizedModelChecksum[k_maxNumberOfMemoizedModels];
   void setMemoizedModelAtIndex(int cacheIndex, Ion::Storage::Record) const;
diff --git a/apps/shared/storage_function_store.h b/apps/shared/storage_function_store.h
index ea246d610..7a733a7f1 100644
--- a/apps/shared/storage_function_store.h
+++ b/apps/shared/storage_function_store.h
@@ -17,7 +17,7 @@ public:
   int numberOfActiveFunctions() const;
   virtual StorageFunction * modelAtIndex(int i) const override { return static_cast<StorageFunction *>(StorageExpressionModelStore::modelAtIndex(i)); }
   virtual StorageFunction * definedModelAtIndex(int i) const override { return static_cast<StorageFunction *>(StorageExpressionModelStore::definedModelAtIndex(i)); }
-  virtual StorageFunction * activeFunctionAtIndex(int i);
+  virtual StorageFunction * activeFunctionAtIndex(int i) const;
 
   virtual char symbol() const = 0;
 };