was advisable to

[navi tasan]

1-It was advisable for him to apply.
2-It was advisable for him to have applied.
3-It would have been advisable for him to apply.

Which of the above correspond to which of the below:
a-we don't know if he applied or not
b-we know that he did not apply


It seems to me that 1 corresponds to "a" and "3" corresponds to "b". I find "2" strange.

[billmcd]

1-It was advisable for him to apply.
2-It was advisable for him to have applied.
3-It would have been advisable for him to apply.

Which of the above correspond to which of the below:
a-we don't know if he applied or not
b-we know that he did not apply


It seems to me that 1 corresponds to "a" and "3" corresponds to "b". I find "2" strange.

1) Yes, "a", but could also be that we know that he did apply.
2) My initial inference would be that we know that he applied, as in a response to "Do/did you know that John applied for the position?"
3) Yes "b"

Of course, as in all cases, context is key and in your examples the statements preceding the responses would suggest the appropriate response.