I have recently been reading Alan Turing's On the Computable Numbers, With an Application to the Entscheidungsproblem, and found it fairly straight forward at first, but was confused on some points in §5 and §8.
Firstly, in §5 page 240, Turing switches to a new way of notation, in which each lines operation will contain a print, saying that lines that will neither print nor erase, can be written like so: q1 Sj PSj q2 However, a paragraph down the page, when he explains how to convert m-configurations to strings of letters, he provides no equivalent, 'D' is erase, 'DA' is print 0, and 'DAA' is print 1. How would someone express printing nothing with a string of letters?
Second, in §8 page 247, I am confused about Turing's description of H. What does Turing mean "The machine H has its motion divided into sections," does he mean each square is a section? Are sections more than one square long?
Lastly, on the same page and section, Turing uses a constant or function, not sure which, R. He uses expretions such as R(N-1), is R being multiplied by N-1? But how can R(N-1) of the sections where there are N sections be found unless R<1? If R<1 why not say (N-1)/R? What exactly is R doing here?
The PDF I used: https://www.cs.virginia.edu/~robins/Turing_Paper_1936.pdf
