很多人会为情人节礼物烦恼不已：玫瑰花？巧克力？其实很多时候不需要体积庞大，也不需要价格不菲，只要用心就能打动他/她。今年的2.14你想好送什么了吗？看看John的idea能不能为大家提供一点启示。 Mathematical Aphrodisiac 甜蜜的数字 By Alex Galt 译 梁碧滢 文章难度 2个辣椒 In the days when John and I used to break up all the time, we made a decision to see each other only casually. Dates were okay, but no more than once a week. We were going to lead separate lives and get together occasionally when the spirit moved us, without worrying about commitment. One day during this period, we were sitting together on the floor of John’s apartment. He was 1)knitting himself a sweater and I was reading [1]Fermat’s Last Theorem. Every now and then, I’d interrupt his knitting to read him passages from my book. “Did you ever hear of [2]amicable numbers? They’re like [3]perfect numbers, but instead of being the sum of their own 2)divisors, they’re the sum of each others divisors. In the Middle Ages people used to carve amicable numbers into pieces of fruit. They’d eat the first piece themselves and then feed the other to their lover. It was a mathematical 3)aphrodisiac. I love that.” John showed little interest. He doesn’t like math much. Not like I do. It was one more reason for us to be casual. Valentine’s Day fell during this period, but we were too casual for presents. While shopping for my grandma’s birthday, however, I saw a 4)crossword puzzle book. We had always worked on the crossword puzzles at the back of The Nation, and for five 5)bucks I figured I could give it to him. When Valentine’s Day rolled around, I handed John the book 6)unwrapped, very casual. He didn’t give me anything at all. I wasn’t surprised. The next day, John invited me over to his apartment. “I have your present,” he said. “Sorry it’s late.” He handed me an 7)awkwardly wrapped 8)bundle. When I opened it, a 9)rectangle of 10)hand-knitted 11)fabric fell on my 12)lap. I picked it up and looked at it, completely confused. One side had the number 124,155 knitted into it; the other side had 100,485. When I looked up at John again, he was barely able to contain his excitement anymore. “They’re amicable numbers,” he said. “I wrote a computer program and let it run for twelve hours. These were the biggest ones I found, and then I double-knitted them in. I thought you might like it.” After that day, we were a lot of things, but “casual” wasn’t one of them. The ancient mathematical aphrodisiac had worked again. 有段时间跟约翰总是三天两头就闹分手，于是我们决定只偶尔见见面。约会可以，不过一周不超过一次。我们各自生活，兴起才偶尔聚聚，不必考虑什么承诺。 在这期间的某一天，在约翰家里，我们坐在地板上，他在给自己织毛衣，而我则在钻研费马最后定理。我不时打断他，从书里挑些片段读给他听。 “你听说过亲和数这概念吗？跟完全数差不多，但这两个数不是自己约数的总和，而是对方约数的总和。在中世纪，人们会把一组亲和数刻在水果切块上。他们会自己先吃一块，然后喂另一块给情人。这是数字催情剂啊，我喜欢。”约翰显得不怎么感兴趣。他一向不太喜欢数学，跟我不同。这也是我们关系疏离的又一原因。 那时期刚好碰上情人节，我们的关系好像没认真到要给对方送什么礼物。不过，给奶奶买生日礼物的时候，我发现了一本纵横拼字谜的书。我和约翰常常合力填《国家》周报后面那些字谜。而且才五块美金，我想，就买来送给他好了。 到了情人节，我把那书递给了约翰——也没包装，很随便地送给他。他什么也没送给我。我并不惊讶。第二天，约翰请我到他家。“我有份礼物给你。”他说，“对不起，送得有点迟。” 他递给我一捆包裹得很笨拙的东西。当我打开时，一块长方形的手工织物掉到我腿上。我拿起来看，全然迷惑。那东西一面织了数字124155，另一面织的是100485。我抬头再看约翰，他已难掩兴奋之情：“这是一组亲和数，”他解释道，“我编了个程序，让它运行了十二个小时，这是我能找到的最大一组亲和数，然后我把它们织进布料的两面，我想你也许会喜欢。” 那天之后，怎么说，我们再也不是随随便便的一对。古老的数字催情剂又一次发挥了作用。 单词注释 1) knit [] v. 编织 2) divisor [] n. 除数，约数 3) aphrodisiac [] n. 催情剂 4) crossword puzzle 纵横拼字谜 5) buck [] n. <美口> 元 6) unwrap [] v. 打开，展开 7) awkwardly [] adv. 笨拙地 8) bundle [] n. 捆，包 9) rectangle [] n. 长方形，矩形 10) hand-knitted 手工编织的 11) fabric [] n. 织物，布 12) lap [] n. (坐时的)大腿前部 小资料 [1] Fermat’s Last Theorem 费马，17世纪法国数学家，习惯在书的页边写下猜想，费马大定理（当n>2时，就找不到满足xn +yn = zn的整数解）是其中困扰数学家们时间最长的，所以被称为“费马最后的定理”——公认为有史以来最著名的数学猜想。 [2] amicable number 亲和数。若自然数M的全部正因子（去掉其本身）之和，恰为自然数N，而N的全部正因子（去掉其本身）之和，恰为自然数M，则称M、N为一对亲和数。 毕达哥拉斯发现的220与284，是人类认识的第一对亲合数，也是最小的一对亲和数： 220本身以外的因数有1，2，4，5，10，11，20，22，44，55，110 284本身以外的因数有1，2，4，71，142 1+2+4+5+10+11+20+22+44+55+110=284 1+2+4+71+142=220 很奇妙吧，在枯燥的数字之间竟然有这种“我中有你，你中有我”的亲密无间的“相亲数”， 而220与284这组数则被称为友谊的象征。 [3] perfect number 完全数。这些特殊的自然数的所有正因子（即除了自身以外的约数）之和（即因子函数），恰好等于它本身。例如：第一个完全数是6，它有约数1，2，3，6，除去它本身6外，其余3个数相加，1＋2＋3＝6。 本文来源：https://www.wddqw.com/doc/131f0948767f5acfa1c7cd0a.html