We have been a few postdocs in a reading group on a specific research topic, sporadically meeting up (via Zoom) for over a year now.
This started out of scientific curiosity and none of us is terrible familiar with the topic. Our ulterior motive has been to set up a paper in the end.
Problem: one individual in our group, Person A, has been ghosting both of us for several months now.
We have been friends for several years but roughly since the beginning of the year, that person has stopped reacting on my attempts at communication. The last time we happened to run into each other at a department picnic, that person has avoided any communication with me, even avoiding eye contact.
I don't know what happened and speculation is rather pointless. I'm wondering more concretely how to move on with the research side project of ours.
The remaining two of us would be able to set up on something on our own. Considering Person A's behavior, I'd rather not see them on the project (personal gut feeling).
How do we get Person A off the project without committing unfair conduct in the eyes of the research community? I believe the inaction on their side is already a quiet retreat from any collaboration, but they could later on claim to have been pushed out by us against their will.