圖靈機

1. 讀取讀取器下嗰格係乜符號；
2. 編輯嗰格－寫一個新嘅符號落去或者刪除咗嗰格佢；
3. 將條帶向左或者向右移一格，等個讀取器可以讀取打前嗰個格隔離嘅一個格。

例子

• `\$0010\$0011`（「0010」喺二進制係 2，而「0011」喺二進制係 3）。

```// 由 x 嗰度減 1，再加 1 落 y 嗰度，直至 x = 0 為止。
repeat until x == 0, then HALT {
// 用 T2（睇下面）
subtract 1 from x
// 用 T1（睇下面）

go back to the first \$
}
```

T2（將個數減 1）如下：

1. 攞補充－將 1 冚唪唥變做 0，0 冚唪唥變做 1；
2. 將個數加 1（睇 T1）；
3. 再做一次補充。

T1（將個數加 1）如下：

1. 如果喺個數嘅左邊盡頭（\$）起始，行去個數嘅右邊盡頭；
2. 由右邊開始行，將所有 1 變做 0，直至
3. 將第一個 0 變成 1。

參考

• B. Jack Copeland ed. (2004), The Essential Turing: Seminal Writings in Computing, Logic, Philosophy, Artificial Intelligence, and Artificial Life plus The Secrets of Enigma, Clarendon Press (Oxford University Press), Oxford UK, ISBN 0-19-825079-7. Contains the Turing papers plus a draft letter to Emil Post re his criticism of "Turing's convention", and Donald W. Davies' Corrections to Turing's Universal Computing Machine.
• Martin Davis (ed.) (1965), The Undecidable, Raven Press, Hewlett, NY.
• Emil Post (1936), "Finite Combinatory Processes—Formulation 1", Journal of Symbolic Logic, 1, 103–105, 1936. Reprinted in The Undecidable, pp. 289ff.
• Emil Post (1947), "Recursive Unsolvability of a Problem of Thue", Journal of Symbolic Logic, vol. 12, pp. 1–11. Reprinted in The Undecidable, pp. 293ff. In the Appendix of this paper Post comments on and gives corrections to Turing's paper of 1936–1937. In particular see the footnotes 11 with corrections to the universal computing machine coding and footnote 14 with comments on Turing's first and second proofs.

攷

1. Hodges, Andrew (2012). Alan Turing: The Enigma (The Centenary Edition). Princeton University Press.
2. Petzold, C. (2008). The annotated Turing: a guided tour through Alan Turing's historic paper on computability and the Turing machine. Wiley Publishing.
3. Rabin, Michael O. (June 2012). Turing, Church, Gödel, Computability, Complexity and Randomization: A Personal View 互聯網檔案館歸檔，歸檔日期2019年6月5號，..