Response/Precedence implicit?

Consider the following log skeleton:

Question: Are the Response and Precedence relations between D and F implicit?

The path from D to E to F seems to suggest that these relations are indeed implicit, but this suggestion is wrong, as is shown by the absence of these relations between A and C: D has F as Response, but A does not have C as Response. The traces used for this log skeleton are:

  • A,B,C
  • C,A
  • D,E,F
  • D,F

Clearly, because of the second trace, A does not have C as Response. As a result, the Response and Precedence between D and F are not implicit.