为什你的耳机总是缠绕打结_BEC初级作文

为什你的耳机总是缠绕打结

Humans have been tying things up with string for many thousands of years, so it’s no surprise mathematicians have been working on theories of knots for a long time. But it wasn’t until the 1800s that the field really took off, when physicists like Lord Kelvin and James Clerk Maxwell were modeling atoms as spinning vortices in the luminiferous ether (a hypothetical substance that permeated all space through which light waves were said to travel). The physicists had worked out some interesting properties of these knot-like atoms and asked their mathematician friends for help with the details. The mathematicians said, “Sure. That’s really interesting. We’ll get back to you on that.”

人类用线绳捆系东西的习惯已经维持上千年，因此数学家们长久以来研究绳结的理论这事情一点也不稀奇。但是直到诸如开尔文男爵和詹姆斯·克拉克·麦克斯韦利用原子建模描述以太（一种假象的无所不在的光波传播介质）介质中的漩涡流的19世纪，这一领域才有所突破。物理学家们发现了这种类似绳结的球棍原子模型的一些有趣的性质，并找来他们的数学家朋友在细节上予以他们帮助。数学家们说：“行，这还真挺有趣，我们来帮你们吧。”

Now, 150 years later, physicists have long since abandoned both the luminiferous ether and knotted atomic models. But mathematicians have created a diverse branch of study known as knot theory that describes the mathematical properties of knots. The mathematical definition of a knot involves tangling a string around itself and then fusing its ends together so the knot can’t be undone (Note: This is kind of hard to do in reality). Using this definition, mathematicians have categorized different knot types. For instance, there is only one type of knot where a string crosses itself three times, known as a trefoil. Similarly, there is only one four-crossing knot, the figure eight. Mathematicians have identified a group of numbers called Jones polynomials that define each type of knot. Still, for a long time knot theory remained a somewhat esoteric branch of mathematics.