For any positive integer x, let xR be the integer whose binary representation isthe reverse of the binary representation of x. (Assume no leading in the binary representation of x.) Define the function R+:NNwhereR+(x)=x+xR.
a. Let A2=x,y|R+(x)=y.

ShowA2L.
b. Let A2=x,y|R+(R+(x))=y. ShowA3L.

Short Answer

Expert verified

(a), the machine has been performed from the computation between x and xR. So, the language A2Lhas been proved.

(b), the language A3Lhas been proved by using computation.

Step by step solution

01

Reverse of integer x

x is one of the positive integers and the reverse of integer x is donated by the symbol xRin the binary representation.

Function R+defined in such a way that the integer x is a natural number.

R+(x)=x+xR

By replacing ones with zeros and zeros with ones, the binary representation is reversed.

02

To Explain the A2={⟨x,y⟩|R+(x)=y} and to show the A3∈L

Consider the Turing machineM, which computes the inverse of every positive integer x. When the integer x is multiplied by the inverse of the integer x, the result is also x.

This is due to the fact that when a binary number1is added to a number 0, the result is always 1. The binary representation of x is transformed here, however the binary representation x of must not include 0.

Only x values with a binary representation of 1 will be accepted by a Turing machine. Even a Turing machine will accept inverse of x values with a binary representation of 0.

Following that, the machine computes the difference between x and xR.

Thus, the language A2Lhas been proved.

03

To Explain the Turing Machine A2={⟨x,y⟩|R+(R+(x))=y}and show A3∈L

Consider the Turing machine M, which computes the inverse of every positive integer x. When the integer is multiplied by the inverse of the integer x, the result is also x.

This is due to the fact that when a binary number1 is added to a number 0, the result is always 1. The binary representation of x is transformed here, however the binary representation of x must not include 0.

Only x values with a binary representation of 1 will be accepted by a Turing machine. Even a Turing machine will accept inverse of x values with a binary representation of 0. Following that, the machine computes the difference between x and xR.

Thus, the languageA3L has been proved.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

a. Let ADD={x,y,z|x,y,z>0 are binary integers and x+y=z}. Show
that ADDL.
b. Let PAL_ADD={x,y|x,y>0are binary integers wherex+y is an integer whose binary representation is a palindrome). (Note that the binary representation of the sum is assumed not to have leading zeros. A palindrome is a string that equals its reverse.) Show that PAL_ADDL.

The cat-and-mouse game is played by two players, "Cat" and "Mouse," on an arbitrary undirected graph. At a given point, each player occupies a node of the graph. The players take turns moving to a node adjacent to the one that they currently occupy. A special node of the graph is called "Hole." Cat wins if the two players ever occupy the same node. Mouse wins if it reaches the Hole before the preceding happens. The game is a draw if a situation repeats (i.e., the two players simultaneously occupy positions that they simultaneously occupied previously, and it is the same player's turn to move).
HAPPY-CAT={<G,c,m,h>G,c,m,hAre respectively a graph and positions of the Cat, Mouse, and Hole, such that Cat has a winning strategy if Cat moves first}.
Show thatHAPPY-CAT is in P. (Hint: The solution is not complicated and doesn't depend on subtle details in the way the game is defined. Consider the entire game tree. It is exponentially big, but you can search it in polynomial time.)

Define CYCLE= {(G)| G is a directed graph that contains a directed cycle}. Show that CYCLEis NL-complete.

Show that PSPACE is closed under the operations union, complementation, and star.

Let .EQREX={(R,S)|R  and   S   are    equivalent   regular  expressions}Show that EQREXPSPACE.

See all solutions

Recommended explanations on Computer Science Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free