• Status: Solved
• Priority: Medium
• Security: Public
• Views: 272

# explanation of hierarchical notation of turing machine

I have difficulties to understand the hierarchical notation of turing machine which is shown in the attached photo. Note that this is not assignment , it is already question and solution in the book but i didn't understand the solution. Please tell me the solution step by step , i didn't understand it.(i must understand it because it can be asked in final exam.) Or if you find and understand similar questions , you can explain it too.
Similar examples and the topic exist in the below links:

Any help is much appreciated.
turing-example.png
0
codeBuilder
1 Solution

Commented:
What question, and what solution are you asking for an explanation of?
0

Commented:
Your question is unclear and I am not exactly sure what you mean by Hierarchical Notation. The mechanics and underlying principles of Tiring Machines are very simple. The notation is a classic example of a notation being more complex than the concept it is trying to represent.
0

Author Commented:
I assigned a png file. There are 2 questions and their answers in this png. But i didn't understand the answer. I want to learn solution step by step..
0

Author Commented:
What does
R -> U R^2U a L^2U a
mean in the first question in png ?
Could you explain it?
0

Commented:
U: write a blank
R^2U: shift right until you hit a blank twice (so skip the first blank and stop at the second one)
a: print the a
L^2U: shift left until you hit a blank twice
a: print the a
0

Commented:
In your lecture notes that you posted they define some shorthand. Technically "shift right until the read head is over x" is not a valid Turing machine command, but you can create a machine that would do that. They use R subscript x to indicate such a machine.
And of course R^2 subscript x means do it twice.
0

Author Commented:
clear explanation
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

## Featured Post

Tackle projects and never again get stuck behind a technical roadblock.