I got a stack exchange email, and the partial first line indicated that the OP wanted to ask me additional questions about my answer. However, when I clicked on the thread, that question was gone. I am wondering if one of the moderators deleted it because it was not really relevant (wouldn't know because I never saw the question). However, the OP is a student, and I would like to respond to student questions. Is there some way to move that potential discussion to a chat, and if so how? Or could OP send me a private message and if so, how?