namespace hpx {
  namespace parallel {
    namespace v1 {
      struct parallel_execution_policy;
      struct sequential_execution_policy;
      struct parallel_vector_execution_policy;
      struct task_execution_policy;
      template<typename T> struct is_execution_policy;
      template<typename T> struct is_parallel_execution_policy;
      template<typename T> struct is_sequential_execution_policy;

      class execution_policy;

      static parallel_execution_policy const par;      // Default parallel execution policy object. 
      static sequential_execution_policy const seq;      // Default sequential execution policy object. 
      static parallel_vector_execution_policy const par_vec;      // Default vector execution policy object. 
      static task_execution_policy const task;      // Default vector execution policy object. 
    }
  }
}