Thanks, you are right and the thing I actually typed was wrong. (For the graph A → C ← B, the collider C blocks the path between A and B, but conditioning on the collider un-blocks it.) Fixed.
Thanks, you are right and the thing I actually typed was wrong. (For the graph A → C ← B, the collider C blocks the path between A and B, but conditioning on the collider un-blocks it.) Fixed.