雙語暢銷書《艾倫圖靈傳》第5章:解謎接力賽(26)
There were a number of ways of using this information to derive the state of the Enigma machine from which all those six-letter sequences had emanated.
But particularly significant was a method which responded to the mechanical work of the cipher clerk, with a mechanised form of analysis.
其中最重要的一種方法，是通過一套機械的分析形式，來應對操作員的機械式工作。They wrote these tables of letter connections in the form of cycles.
他們用輪換的形式來描述這些字母關係，
The cycle notation was common currency in elementary group theory.
這是基礎羣論中很常用的方法。To bring the specific letter connection above into 'cycle' form, one would start with the letter A, and note that A was connected with R.
要把一組特定的字母關係表示爲輪換形式，首先從字母A開始，記下A連着R，Then R was connected with B, B with G, G with M, M with W, W with Z, Z with C, C with Z, Z with U, U with K, and K with A—making a complete 'cycle':
接着找到R連着B，以此類推B連着G, G連着M, M連着W, W連着T, T連着C, C連着Z, Z連着U, U連着K, K連着A，這樣就形成了一個完整的輪換：(A R B G M W T C Z U K). The complete connection could be written out as the product of four cycles:
（ARBGMWTCZUK）。所有的字母關係可以表示爲4個輪換：The reason for doing this was that the analysts had noticed that the lengths of these cycles (in this example, 11, 11, 2, 2) were independent of the plugboard.
這樣做的原因是，分析人員發現，這些輪換的長度（在這個例子中是11, 11, 2，2）與配線板無關，它們只取決於盤位。They would depend only upon the position of the rotors, the plugboard affecting which letters appeared in the cycles, but not how many.
配線板影響輪換中的字母，但不會影響輪換長度。
