diff --git a/include/nil/crypto3/zk/snark/arithmetization/plonk/copy_constraint.hpp b/include/nil/crypto3/zk/snark/arithmetization/plonk/copy_constraint.hpp
index 4140e6a1..f0594194 100644
--- a/include/nil/crypto3/zk/snark/arithmetization/plonk/copy_constraint.hpp
+++ b/include/nil/crypto3/zk/snark/arithmetization/plonk/copy_constraint.hpp
@@ -38,16 +38,17 @@ namespace nil {
 
                 template<typename FieldType>
                 struct plonk_copy_constraint {
-                    plonk_copy_constraint() = default;
-                    plonk_copy_constraint(const plonk_copy_constraint<FieldType> &other){
-                        initialize(other.first, other.second);
+                    plonk_copy_constraint() = delete;
+                    plonk_copy_constraint(const plonk_copy_constraint<FieldType> &other): first(other.first), second(other.second) {
+                        initialize(first, second);
                     }
                     plonk_copy_constraint(
                         const plonk_variable<typename FieldType::value_type> &_first,
                         const plonk_variable<typename FieldType::value_type> &_second
-                    ){
+                    ): first(_first), second(_second) {
                         initialize(_first, _second);
                     }
+
                     plonk_variable<typename FieldType::value_type> first;
                     plonk_variable<typename FieldType::value_type> second;
                     bool operator==(const plonk_copy_constraint<FieldType> &other){
@@ -67,6 +68,12 @@ namespace nil {
                             std::swap(first, second);
                         }
                    }
+
+                   void swap() {
+                       const auto tmp = first;
+                       first = second;
+                       second = tmp;
+                   }
                 };
 
                 template <typename FieldType>
diff --git a/include/nil/crypto3/zk/snark/arithmetization/plonk/table_description.hpp b/include/nil/crypto3/zk/snark/arithmetization/plonk/table_description.hpp
index ffc1694d..fa4ea3e1 100644
--- a/include/nil/crypto3/zk/snark/arithmetization/plonk/table_description.hpp
+++ b/include/nil/crypto3/zk/snark/arithmetization/plonk/table_description.hpp
@@ -74,10 +74,6 @@ namespace nil {
                                 return witness_columns + public_input_columns + a.index;
                             case plonk_variable<typename FieldType::value_type>::column_type::selector:
                                 return witness_columns + public_input_columns + constant_columns + a.index;
-                            case plonk_variable<typename FieldType::value_type>::column_type::uninitialized:
-                                std::cerr << "trying to access uninitialized var!";
-                                std::abort();
-                                break;
                         }
                         /* unreachable*/
                         return std::numeric_limits<size_t>::max();
diff --git a/include/nil/crypto3/zk/snark/arithmetization/plonk/variable.hpp b/include/nil/crypto3/zk/snark/arithmetization/plonk/variable.hpp
index e8b0f469..6d584492 100644
--- a/include/nil/crypto3/zk/snark/arithmetization/plonk/variable.hpp
+++ b/include/nil/crypto3/zk/snark/arithmetization/plonk/variable.hpp
@@ -69,7 +69,7 @@ namespace nil {
                     using assignment_type = AssignmentType;
 
                     enum column_type : std::uint8_t {
-                        witness, public_input, constant, selector, uninitialized
+                        witness, public_input, constant, selector
                     };
 
                     /**
@@ -80,7 +80,11 @@ namespace nil {
                     bool relative;
                     column_type type;
 
-                    constexpr plonk_variable() : index(0), rotation(0), relative(false), type(column_type::uninitialized) {};
+                    constexpr plonk_variable() = delete;
+
+                    constexpr plonk_variable(const plonk_variable &other) :
+                            index(other.index),
+                            rotation(other.rotation), relative(other.relative), type(other.type) {};
 
                     constexpr plonk_variable(const std::size_t index,
                                              std::int32_t rotation,
@@ -176,8 +180,7 @@ namespace nil {
                             {plonk_variable<AssignmentType>::column_type::witness,      "w"},
                             {plonk_variable<AssignmentType>::column_type::public_input, "pub"},
                             {plonk_variable<AssignmentType>::column_type::constant,     "c"},
-                            {plonk_variable<AssignmentType>::column_type::selector,     "sel"},
-                            {plonk_variable<AssignmentType>::column_type::uninitialized,"NaN"}
+                            {plonk_variable<AssignmentType>::column_type::selector,     "sel"}
                     };
                     os << type_map[var.type] << "_" << var.index;
                     if (!var.relative) {
diff --git a/include/nil/crypto3/zk/snark/systems/plonk/placeholder/gates_argument.hpp b/include/nil/crypto3/zk/snark/systems/plonk/placeholder/gates_argument.hpp
index 92ce849d..cb46911d 100644
--- a/include/nil/crypto3/zk/snark/systems/plonk/placeholder/gates_argument.hpp
+++ b/include/nil/crypto3/zk/snark/systems/plonk/placeholder/gates_argument.hpp
@@ -107,10 +107,6 @@ namespace nil {
                                 case polynomial_dfs_variable_type::column_type::selector:
                                     assignment = assignments.selector(var.index);
                                     break;
-                                case polynomial_dfs_variable_type::column_type::uninitialized:
-                                    std::cerr << "trying to access uninitialized var!";
-                                    std::abort();
-                                    break;
                             }
 
                             if (var.rotation != 0) {
diff --git a/include/nil/crypto3/zk/snark/systems/plonk/placeholder/lookup_argument.hpp b/include/nil/crypto3/zk/snark/systems/plonk/placeholder/lookup_argument.hpp
index 1dafb48c..dc1acca6 100644
--- a/include/nil/crypto3/zk/snark/systems/plonk/placeholder/lookup_argument.hpp
+++ b/include/nil/crypto3/zk/snark/systems/plonk/placeholder/lookup_argument.hpp
@@ -462,10 +462,6 @@ namespace nil {
                                 case DfsVariableType::column_type::selector:
                                     assignment = assignments.selector(var.index);
                                     break;
-                                case DfsVariableType::column_type::uninitialized:
-                                    std::cerr << "trying to access uninitialized var!";
-                                    std::abort();
-                                    break;
                             }
 
                             if (var.rotation != 0) {