AOS and Travel

[svirk]

I have following questions;

1) When is AOS considered in process? The day application reaches at USCIS or When they issue the receipt?

2) Say you have Canadian PP with TN (unexpired) and you have not received AOS receipt yet. And you go to Canada for a short trip, on re-entry how do people at the border will know that you have applied for AOS? They never stamp the PP either.


Thanks.