In the first chapter, it is mentioned that: "In other words A ≤ B in the poset if “A implies B”, often denoted A ⇒ B." An example could be: A: If it rains. B: The match wont happen. A => B. It can be seen that A = True then B = False. But if A = False, then B = True or False. Based on this we can say A <= B. Are there other explanations for this statement?