| Abstract in English | 第1-5页 |
| Abstract in Chinese | 第5-7页 |
| Chapter One Introduction | 第7-17页 |
| 1．1 The review of the digital problems | 第7-15页 |
| 1．2 The main results | 第15-17页 |
| Chapter Two Proof of Theorem 1 | 第17-23页 |
| Chapter Three Proof of Theorem 2 and Applications | 第23-26页 |
| References | 第26-28页 |