Exercise 4.65 · 习题

Exercise 4.65: Cy D. Fect, looking forward to
the day when he will rise in the organization, gives a query to find all the
wheels (using the wheel rule of 4.4.1):

(wheel ?who)

To his surprise, the system responds

;;; Query results:
(wheel (Warbucks Oliver))
(wheel (Bitdiddle Ben))
(wheel (Warbucks Oliver))
(wheel (Warbucks Oliver))
(wheel (Warbucks Oliver))

Why is Oliver Warbucks listed four times?

练习 4.65：Cy D. Fect 憧憬着自己在组织中出人头地的那一天，发出查询以找出所有的"核心人物"（使用 4.4.1 中的 wheel 规则）：

(wheel ?who)

令他惊讶的是，系统的响应如下：

;;; Query results:
(wheel (Warbucks Oliver))
(wheel (Bitdiddle Ben))
(wheel (Warbucks Oliver))
(wheel (Warbucks Oliver))
(wheel (Warbucks Oliver))

Oliver Warbucks 为何被列出四次？