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Dudeney 谜题 22

题面摘自 Henry E. Dudeney 公版文本;英文为古腾堡原文整理,中文为本站自译,提示、解答骨架和闲谈保留本站原创结构。

几何与棋盘 1907 P4 geometricpuzzle

"Speaking of relationships," said the Parson at a certain dinner-party, "our legislators are getting the marriage law into a frightful tangle, Here, for example, is a puzzling case that has come under my notice. Two brothers married two sisters. One man died and the other man's wife also died. Then the survivors married." "The man married his deceased wife's sister under the recent Act?" put in the Lawyer. "Exactly. And therefore, under the civil law, he is legally married and his child is legitimate. But, you see, the man is the woman's deceased husband's brother, and therefore, also under the civil law, she is not married to him and her child is illegitimate." "He is married to her and she is not married to him!" said the Doctor. "Quite so. And the child is the legitimate son of his father, but the illegitimate son of his mother." "Undoubtedly 'the law is a hass,'" the Artist exclaimed, "if I may be permitted to say so," he added, with a bow to the Lawyer. "Certainly," was the reply. "We lawyers try our best to break in the beast to the service of man. Our legislators are responsible for the breed." "And this reminds me," went on the Parson, "of a man in my parish who married the sister of his widow. This man——" "Stop a moment, sir," said the Professor. "Married the sister of his widow? Do you marry dead men in your parish?" "No; but I will explain that later. Well, this man has a sister of his own. Their names are Stephen Brown and Jane Brown. Last week a young fellow turned up whom Stephen introduced to me as his nephew. Naturally, I spoke of Jane as his aunt, but, to my astonishment, the youth corrected me, assuring me that, though he was the nephew of Stephen, he was not the nephew of Jane, the sister of Stephen. This perplexed me a good deal, but it is quite correct." The Lawyer was the first to get at the heart of the mystery. What was his solution?

“说到人际关系,”牧师在一次晚宴上说道,“我们的立法者正在把婚姻法搞得一团糟。例如,我注意到了一个令人费解的案件。两个兄弟娶了两个姐妹。一个男人死了,另一个男人的妻子也死了。然后幸存者结婚了。” “根据最近的法案,该男子与已故妻子的妹妹结婚了?”放入律师。 “没错。因此,根据民法,他是合法结婚的,他的孩子是婚生的。但是,你看,男方是女方已故丈夫的兄弟,因此,根据民法,她也没有与他结婚,她的孩子也是私生子。” “他娶了她,她却没有嫁给他!”医生说。 “正是如此。而且这个孩子是他父亲的嫡子,却是他母亲的私生子。” “毫无疑问,‘法律是一件麻烦事’,”艺术家大声说道,“如果我可以这么说的话,”他向律师鞠了一躬,补充道。 “当然,”他回答道。 “我们律师尽最大努力让野兽为人类服务。我们的立法者对这个品种负责。” “这让我想起,”牧师继续说道,“我教区的一个男人娶了他寡妇的妹妹。这个男人——” “停一下,先生,”教授说。 “娶了他遗孀的妹妹?你娶了你教区的死人吗?” “不;但是我稍后会解释这一点。嗯,这个人有一个自己的妹妹。他们的名字是斯蒂芬·布朗和简·布朗。上周出现了一个年轻人,斯蒂芬向我介绍他是他的侄子。当然,我说简是他的姨妈,但令我惊讶的是,年轻人纠正了我,向我保证,虽然他是斯蒂芬的侄子,但他不是简的侄子,斯蒂芬的妹妹。这让我很困惑,但它是非常正确的。”律师是第一个揭开谜团核心的人。他的解决方案是什么?

提示 1

先说出现象:哪些量会变,哪些约束不会变。

提示 2

找守恒量、相似关系、平衡条件或不变量,不急着代公式。

提示 3

把物理图景或谜题结构翻成一个最小方程组,再处理边界情况。

完整解答

解题主线是先把 Dudeney 谜题 22 的条件整理成一个稳定模型,再选择最少的变量。第一步确认约束,第二步写出关键关系,第三步检查特殊情形。这里给的是原创解法骨架;若要核对原始题面,请回到公版来源。

这类题最怕一上来套公式。先把图景或语言条件说清楚,答案通常会少绕很多路。