Thank you, you're absolutely right: I meant to say P(A | B) > P(A). By excluding !B, you're necessarily excluding only the Nil group. I think I got it right in

Thank you, you're absolutely right: I meant to say P(A | B) > P(A). By excluding !B, you're necessarily excluding only the Nil group. I think I got it right in my edit, but thank you for correcting my thinking here.