diff --git a/setup.py b/setup.py
index d00bfbe..c1d6683 100644
--- a/setup.py
+++ b/setup.py
@@ -40,7 +40,7 @@ def run(self):
         ]
 
         cfg = 'Debug' if self.debug else 'Release'
-        #cfg = 'Debug'
+        cfg = 'Debug'
         build_args = ['--config', cfg]
 
         cmake_args += ['-DCMAKE_BUILD_TYPE=' + cfg]
diff --git a/stator/symbolic/binary_ops_rt.hpp b/stator/symbolic/binary_ops_rt.hpp
index 3e16483..f35fd72 100644
--- a/stator/symbolic/binary_ops_rt.hpp
+++ b/stator/symbolic/binary_ops_rt.hpp
@@ -35,7 +35,8 @@ namespace sym {
     }
     
     bool operator==(const BinaryOp& o) const {
-      return (_l == o._l) && (_r == o._r);
+      //Shortcut comparison before proceeding with item by item
+      return (this == &o) || ((_l == o._l) && (_r == o._r));
     }
 
     template<class RHS>
diff --git a/stator/symbolic/dict_rt.hpp b/stator/symbolic/dict_rt.hpp
index 99b7db1..4faf4ae 100644
--- a/stator/symbolic/dict_rt.hpp
+++ b/stator/symbolic/dict_rt.hpp
@@ -31,6 +31,7 @@ namespace sym {
     }
     
     typedef Store::key_type key_type;
+    typedef Store::value_type value_type;
     typedef Store::reference reference;
     typedef Store::const_reference const_reference;
     typedef typename Store::iterator iterator;
@@ -54,18 +55,76 @@ namespace sym {
     bool empty() const noexcept { return _store.empty(); }
 
     bool operator==(const Dict& o) const {
-      return _store == o._store;
+      //Shortcut comparison before proceeding with item by item
+      return (this == &o) || (_store == o._store);
     }
-    
+
     template<class RHS>
     constexpr bool operator==(const RHS&) const {
       return false;
     }
     
+    std::pair<iterator,bool> insert( const value_type& value ) {
+      return _store.insert(value);
+    }
+    
+    std::pair<iterator,bool> insert( value_type&& value ) {
+      return _store.insert(std::move(value));
+    }
+    
   private:
     Store _store;
   };
 
+  auto operator+(const Dict& l, const Dict& r)  {
+    auto out_ptr = Dict::create();
+    auto& out = *out_ptr;
+    
+    for (const auto& item : l)
+      out.insert(item);
+
+    for (const auto& item : r) {
+      auto it = out.find(item.first);
+      if (it != out.end())
+	out[item.first] = out[item.first] + item.second;
+      else
+	out.insert(item);
+    }
+    
+    return out_ptr;
+  }
+  
+  auto operator-(const Dict& l, const Dict& r)  {
+    auto out_ptr = Dict::create();
+    auto& out = *out_ptr;
+    
+    for (const auto& item : l)
+      out.insert(item);
+
+    for (const auto& item : r) {
+      auto it = out.find(item.first);
+      if (it != out.end())
+	out[item.first] = out[item.first] - item.second;
+      else
+	out[item.first] = -item.second;
+    }
+    
+    return out_ptr;
+  }
+
+  auto operator*(const Dict& l, const Dict& r)  {
+    auto out_ptr = Dict::create();
+    auto& out = *out_ptr;
+    
+    for (const auto& item : l) {
+      auto it = r.find(item.first);
+      if (it != r.end())
+	out[item.first] = item.second * it->second;
+    }
+    
+    return out_ptr;
+  }
+    
   namespace detail {
     template<> struct Type_index<Dict> { static const int value = 16; };
   }
@@ -85,6 +144,9 @@ namespace sym {
     return out;
   }
 
+  std::pair<int, int> BP(const Dict& v)
+  { return std::make_pair(std::numeric_limits<int>::max(), std::numeric_limits<int>::max()); }
+  
   template<class Config = DefaultReprConfig>
   inline std::string repr(const sym::Dict& f)
   {
diff --git a/stator/symbolic/list_rt.hpp b/stator/symbolic/list_rt.hpp
index 1c8851f..ff46b8a 100644
--- a/stator/symbolic/list_rt.hpp
+++ b/stator/symbolic/list_rt.hpp
@@ -53,7 +53,8 @@ namespace sym {
     bool empty() const noexcept { return _store.empty(); }
 
     bool operator==(const List& o) const {
-      return _store == o._store;
+      //Shortcut comparison before proceeding with item by item
+      return (this == &o) || (_store == o._store);
     }
 
     template<class RHS>
@@ -79,7 +80,7 @@ namespace sym {
     return out;
   }
   
-  Expr operator+(const List& l, const List& r) {
+  auto operator+(const List& l, const List& r) {
     if (l.size() != r.size())
       stator_throw() << "Mismatched list size for: \n" << l << "\n and\n" << r;
     
@@ -92,6 +93,45 @@ namespace sym {
     return out;
   }
 
+  auto operator-(const List& l, const List& r) {
+    if (l.size() != r.size())
+      stator_throw() << "Mismatched list size for: \n" << l << "\n and\n" << r;
+    
+    auto out = List::create();
+    out->resize(l.size());
+    
+    for (size_t idx(0); idx < l.size(); ++idx)
+      (*out)[idx] = l[idx] - r[idx];
+    
+    return out;
+  }
+
+  auto operator*(const List& l, const List& r) {
+    if (l.size() != r.size())
+      stator_throw() << "Mismatched list size for: \n" << l << "\n and\n" << r;
+    
+    auto out = List::create();
+    out->resize(l.size());
+    
+    for (size_t idx(0); idx < l.size(); ++idx)
+      (*out)[idx] = l[idx] * r[idx];
+    
+    return out;
+  }
+
+  auto operator/(const List& l, const List& r) {
+    if (l.size() != r.size())
+      stator_throw() << "Mismatched list size for: \n" << l << "\n and\n" << r;
+    
+    auto out = List::create();
+    out->resize(l.size());
+    
+    for (size_t idx(0); idx < l.size(); ++idx)
+      (*out)[idx] = l[idx] / r[idx];
+    
+    return out;
+  }
+  
   Expr simplify(const List& in) {
     auto out_ptr =  List::create();
     auto& out = *out_ptr;
@@ -104,8 +144,12 @@ namespace sym {
     return out_ptr;
   }
 
+  std::pair<int, int> BP(const List& v)
+  { return std::make_pair(std::numeric_limits<int>::max(), std::numeric_limits<int>::max()); }
+
+  
   template<class Config = DefaultReprConfig>
-  inline std::string repr(const sym::List& f)
+  inline std::string repr(const List& f)
   {
     std::string out = std::string((Config::Latex_output) ? "\\left[" : "[");
     const std::string end = std::string((Config::Latex_output) ? "\\right]" : "]");
diff --git a/stator/symbolic/runtime.hpp b/stator/symbolic/runtime.hpp
index 0fa0b59..b0bc4a9 100644
--- a/stator/symbolic/runtime.hpp
+++ b/stator/symbolic/runtime.hpp
@@ -279,16 +279,14 @@ namespace sym {
       comparisons between RTBase derived types.
      */
     template<class LHS>
-    struct ComparisonVisitor : public sym::detail::VisitorHelper<ComparisonVisitor<LHS> > {
+    struct ComparisonVisitor : public sym::detail::VisitorHelper<ComparisonVisitor<LHS>, bool> {
       ComparisonVisitor(const LHS& l): _l(l) {}
       
-      template<class RHS> sym::Expr apply(const RHS& r) {
-	_result = _l == r;
-	return Expr();
+      template<class RHS> bool apply(const RHS& r) {
+	return _l == r;
       }
 
       const LHS& _l;
-      bool _result;
     };
   }
   
@@ -303,20 +301,16 @@ namespace sym {
     virtual bool compare(const Expr& rhs) const {
       const Derived& lhs(*static_cast<const Derived*>(this));
       detail::ComparisonVisitor<Derived> visitor(lhs);
-      rhs->visit(visitor);
-      return visitor._result;
+      return rhs->visit(visitor);
     }
   };  
 
   namespace detail {
     /*! \brief Binding power visitor for sym::detail::BP(const Expr&). */
-    struct BPVisitor : public sym::detail::VisitorHelper<BPVisitor> {
-      template<class T> sym::Expr apply(const T& rhs) {
-	_BP = BP(rhs);
-	return Expr();
+    struct BPVisitor : public sym::detail::VisitorHelper<BPVisitor, std::pair<int, int>> {
+      template<class T> std::pair<int, int> apply(const T& rhs) {
+	return BP(rhs);
       }
-      
-      std::pair<int, int> _BP;
     };
   }
   
@@ -325,8 +319,7 @@ namespace sym {
   */
   inline std::pair<int, int> BP(const Expr& v) {
     detail::BPVisitor vis;
-    v->visit(vis);
-    return vis._BP;
+     return v->visit(vis);
   }
 }
 
@@ -497,6 +490,16 @@ namespace sym {
 	return Expr(store(Op::apply(l, r)));
       }
 
+      template<class Op>
+      Expr dd_visit(const Dict& l, const Dict& r, Op) {
+	return Expr(simplify(Op::apply(l, r)));
+      }
+
+      template<class Op>
+      Expr dd_visit(const List& l, const List& r, Op) {
+	return Expr(simplify(Op::apply(l, r)));
+      }
+      
       //Direct evaluation of doubles
       template<class T2>
       Expr dd_visit(const double& l, const T2& r, detail::Subtract) {
@@ -873,21 +876,17 @@ namespace sym {
 
   namespace detail {
     template<class Config>
-    struct ReprVisitor : public sym::detail::VisitorHelper<ReprVisitor<Config> > {
-      template<class T> sym::Expr apply(const T& rhs) {
-	_repr = repr<Config>(rhs);
-	return sym::Expr();
+    struct ReprVisitor : public sym::detail::VisitorHelper<ReprVisitor<Config>, std::string> {
+      template<class T> std::string apply(const T& rhs) {
+	return repr<Config>(rhs);
       }
-
-      std::string _repr;
     };
   }
 
   template<class Config>
   std::string repr(const sym::RTBase& b) {
     detail::ReprVisitor<Config> visitor;
-    b.visit(visitor);
-    return visitor._repr;
+    return b.visit(visitor);
   }
 
   /*! \brief Give a representation of an Expr. 
diff --git a/stator/symbolic/unary_ops_rt.hpp b/stator/symbolic/unary_ops_rt.hpp
index 33229c8..ce3fd40 100644
--- a/stator/symbolic/unary_ops_rt.hpp
+++ b/stator/symbolic/unary_ops_rt.hpp
@@ -35,8 +35,9 @@ namespace sym {
       return std::shared_ptr<UnaryOp>(new UnaryOp(arg));
     }
 
-    bool operator==(const UnaryOp<Expr,Op>& o) const {
-      return (_arg == o._arg);
+    bool operator==(const UnaryOp& o) const {
+      //Shortcut comparison before proceeding with item by item
+      return (this == &o) || (_arg == o._arg);
     }
 
     template<class RHS>
diff --git a/stator/symbolic/units.hpp b/stator/symbolic/units.hpp
index 91b0635..78c0699 100644
--- a/stator/symbolic/units.hpp
+++ b/stator/symbolic/units.hpp
@@ -18,3 +18,29 @@
 */
 
 #pragma once
+
+namespace sym {
+  namespace detail {
+    struct Units {
+      static constexpr int leftBindingPower = 60;
+      static constexpr auto associativity = Associativity::LEFT;
+      static constexpr bool commutative = true;
+      static constexpr bool associative = true;
+      typedef NoIdentity left_identity;
+      typedef Unity right_identity;
+      typedef Null left_zero;
+      typedef NoIdentity right_zero;
+      static inline std::string l_repr() { return ""; }
+      static inline std::string repr() { return "{"; }
+      static inline std::string r_repr() { return "}"; }
+      static inline std::string l_latex_repr() { return ""; }
+      static inline std::string latex_repr() { return "\left\{"; }
+      static inline std::string r_latex_repr() { return "\right\}"; }
+      template<class L, class R> static auto apply(const L& l, const R& r) {
+	return BinaryOp<decltype(store(l)), detail::Units, decltype(store(r))>::create(l, r);
+      }
+      static constexpr int type_index = 18;
+    };
+  }
+  
+}
diff --git a/stator/symbolic/variable.hpp b/stator/symbolic/variable.hpp
index 7ea9a85..41a2765 100644
--- a/stator/symbolic/variable.hpp
+++ b/stator/symbolic/variable.hpp
@@ -87,8 +87,7 @@ namespace sym {
 
   namespace detail {
     template<auto N, class ...Args>
-    struct Type_index<Var<N, Args...> >
-    { static const int value = 1;  };
+    struct Type_index<Var<N, Args...> > { static const int value = 1;  };
   }
 }
 
diff --git a/stator/symbolic/variable_rt.hpp b/stator/symbolic/variable_rt.hpp
index 5723d06..8f191b6 100644
--- a/stator/symbolic/variable_rt.hpp
+++ b/stator/symbolic/variable_rt.hpp
@@ -48,7 +48,8 @@ namespace sym {
 
     
     inline bool operator==(const VarRT& o) const {
-      return _name == o._name;
+      //Shortcut comparison before proceeding with string comparison
+      return (this == &o) || (_name == o._name);
     }
 
     template<class RHS>
diff --git a/tests/stator_test.py b/tests/stator_test.py
index 909a0db..374d7f9 100644
--- a/tests/stator_test.py
+++ b/tests/stator_test.py
@@ -13,7 +13,7 @@ def test_interface(self):
         self.assertEqual(repr(Expr("1=1")),"Expr('1=1')")
         self.assertEqual(repr(Expr("x[1]")),"Expr('x[1]')")
 
-    def test_array(self):
+    def test_list(self):
         self.assertEqual(repr(Expr("[]")),"Expr('[]')")
         self.assertEqual(repr(Expr("[1]")),"Expr('[1]')")
         self.assertEqual(repr(Expr("[1, 2]")),"Expr('[1, 2]')")
@@ -22,11 +22,17 @@ def test_array(self):
         df = derivative(f, x)
         self.assertEqual(repr(simplify(df)), "Expr('[0, 1, 4*x]')")
         self.assertEqual(sub(df, Expr('x=2')), [0, 1, 8])
+        self.assertEqual(Expr("[1,2,3,4]") + Expr("[0,1,2,3]"), Expr('[1, 3, 5, 7]').to_python())
+        self.assertEqual(Expr("[1,2,3,4]") - Expr("[0,1,2,3]"), Expr('[1, 1, 1, 1]').to_python())
+        self.assertEqual(Expr("[1,2,3,4]") * Expr("[0,1,2,3]"), Expr('[0, 2, 6, 12]').to_python())
+        self.assertEqual(Expr("[1,2,3,4]") / Expr("[1,2,3,2]"), Expr('[1, 1, 1, 2]').to_python())
         
-
     def test_dict(self):
         self.assertEqual(repr(Expr("{}")),"Expr('{}')")
         self.assertEqual(repr(Expr("{x:1}")),"Expr('{x:1}')")
+        self.assertEqual(Expr("{x:1}") + Expr("{x:1, y:2}"), Expr('{x:2.0, y:2.0}').to_python())
+        self.assertEqual(Expr("{x:1}") - Expr("{x:1, y:2}"), Expr('{x:0, y:-2.0}').to_python())
+        self.assertEqual(Expr("{x:3}") * Expr("{x:2, y:2}"), Expr('{x:6}').to_python())
 
     def test_sub_generic(self):
         self.assertEqual(sub(Expr("x"), Expr('{x:2}')), 2)
diff --git a/tests/symbolic_runtime_test.cpp b/tests/symbolic_runtime_test.cpp
index e3bfa6c..5d87a59 100644
--- a/tests/symbolic_runtime_test.cpp
+++ b/tests/symbolic_runtime_test.cpp
@@ -222,6 +222,7 @@ UNIT_TEST( symbolic_list_basic )
   auto& x = *x_ptr;
   UNIT_TEST_CHECK_EQUAL(sub(Expr("[1, x, y]"), Expr(x=2)), Expr("[1,2,y]"));
   UNIT_TEST_CHECK_EQUAL(derivative(Expr("[1, x, y]"), x), Expr("[0,1,0]"));
+  UNIT_TEST_CHECK_EQUAL(simplify(Expr("[1, 1, 1]")+Expr("[0, 1, 2]")), Expr("[1,2,3]"));
 }
 
 UNIT_TEST( symbolic_dict_basic )
@@ -237,7 +238,7 @@ UNIT_TEST( symbolic_dict_basic )
   v[y] = Expr(3);
   UNIT_TEST_CHECK_EQUAL(sub(Expr("x"), v), Expr("2"));
   UNIT_TEST_CHECK_EQUAL(sub(Expr("y"), v), Expr("3"));
-
+  UNIT_TEST_CHECK_EQUAL(sub(Expr("[1, x, y]"), Expr("{x:2, y:3}")), Expr("[1,2,3]"));
   UNIT_TEST_CHECK_EQUAL(sub(Expr("[1, x, y]"), v), Expr("[1,2,3]"));
 }