Symbols | Dynamic relationships |
| x and y are independent |
| x and y are contemporaneous correlative |
| Use the past and simultaneous information of y to predict x |
| Use the past information of y to predict x |
| Use the past and simultaneous information of x to predict y |
| Use the past information of x to predict y |
| The past and simultaneous of x and y are interactive |
| The past of x and y are interactive |