Does a divorce take place if a man says to his wife: "You are divorced if you do such and such," knowing that he is unaware if the wife did that action, and he had not divorced her before, and he had intercourse with her two weeks later?

A husband's statement to his wife, "Consider yourself divorced," is among the ambiguous expressions (kinayat) by which divorce does not occur unless intended. If the husband intended by his statement to make the divorce contingent on a specific action by the wife, then it is a contingent divorce. If the wife performs the action upon which the divorce was made contingent, then the oath (or condition) has been broken. If the wife does not inform him of this, there is no sin upon him, and the sin is upon her for concealing what ought to be disclosed.