Will resolve based on my future best guess of whether she had covid on September 4.

On Friday August 29 I went to a conference (Less Wrong Community Weekend) with about 200-250 attendees. Everyone was required to test for covid on arrival, and would have been turned away if positive, though I don't know if anyone checked that late tested. The conference ended on Monday September 1, a bunch of people from it still hung out until Tuesday September 2, which is the day I flew home. I spent that night and the next with my girlfriend.

Various people from the conference tested positive at various times. I think all after it had ended, but we weren't required to test daily during the conference. I myself first tested on Thursday September 4. I used two expired tests, both with strong positive lines, while my girlfriend got two negative results from expired tests. Then she went to get fresh tests, where I got a somewhat fainter positive line and she still got a negative result. We decided that she'd go home to her other boyfriend, and come back if she developed symptoms or tested positive. (Trying to balance "risk that she hasn't got it yet but catches it from me by staying" against "risk that she has got it and infects her other boyfriend".)

The question is whether she was already infected when she left. Most likely scenarios are that she obviously develops covid in the next few days, and I decide it's probably related, and resolve yes; or she doesn't seem to develop it for at least two weeks, and I decide she probably didn't have it, and resolve no.

Memory of symptoms: at some point during the conference I got symptoms that just seemed like a cold. I think it was just a slightly runny nose. They didn't get worse. On the Wednesday evening I started to feel a tickle in my throat, it was more obvious during the day Thursday, and at some point I had a brief coughing fit (not in the flat or near my girlfriend, so she wouldn't have got it from that specifically).