据我了解，模态量词可能会放宽逻辑合取的行为：
(true) and (possibly false) => true
(true) and (possibly unknown) => true
(possibly true) and (possibly false) => true
(possibly true) and (possibly unknown) => true
(necessarily true) and (possibly false) => true
(necessarily true) and (possibly unknown) => true
(unknown) and (possibly false) => unknown
(possibly unknown) and (possibly false) => unknown
(necessarily unknown) and (possibly false) => unknown
我的问题是：它对其他操作（如独占析取、蕴涵和等价）有什么具体影响吗？这些例子怎么样（我自己想不通）：
(true) xor (possibly true) => true | false ?
(true) xor (possibly unknown) => true | unknown ?