Two-tape turing machine, Theory of Computation

Assignment Help:

Let there L1 and L2 . We show that L1 ∩ L2 is CFG .

Let M1 be a decider for L1 and M2 be a decider for L2 .

Consider a 2-tape TM M:

"On input x:

1. copy x on the second tape

2. on the ?rst tape run M1 on x

M=

3. if M1 accepted then goto 4. else M rejects

4. on the second tape run M2 on x

5. if M2 accepted then M accepts else M rejects."

The machine M is a decider and it accepts a string x i? both M1 and M2 accept x.

Two-tape TM is as expressive as the single tape TM.

The process is as follows

"Given a CFG G and a string w , does G generate w ?

Language Formulation (Acceptance Problem for CFG) def

ACFG = {?G , w ? | G is a CFG, w a string and w ∈ L(G )}

The language ACFG is decidable.

 Construct a decider M for ACFG :M = " 1. On input x check if x = ?G , w ? where

G is an CFG and w is a string, if not then M rejects.

2. Convert G into Chomsky normal form.

3. List all derivations in G of length exactly 2|w | - 1,

if w = ? then check if there is the rule S → ?.

4. If w is ever generated then M accepts, else M rejects."


Related Discussions:- Two-tape turing machine

Ogdens lemma, proof ogdens lemma .with example i am not able to undestand ...

proof ogdens lemma .with example i am not able to undestand the meaning of distinguished position .

Design and implementation of the state machine, You are required to design ...

You are required to design a system that controls the speed of a fan's rotation. The speed at which the fan rotates is determined by the ambient temperature, i.e. as the temperatur

Computer Simulation, Generate 100 random numbers with the exponential distr...

Generate 100 random numbers with the exponential distribution lambda=5.0.What is the probability that the largest of them is less than 1.0?

Kleenes theorem, All that distinguishes the de?nition of the class of Regul...

All that distinguishes the de?nition of the class of Regular languages from that of the class of Star-Free languages is that the former is closed under Kleene closure while the lat

Chomsky normal form, s->0A0|1B1|BB A->C B->S|A C->S|null find useless symbo...

s->0A0|1B1|BB A->C B->S|A C->S|null find useless symbol?

what is a turing machine, A Turing machine is a theoretical computing mach...

A Turing machine is a theoretical computing machine made-up by Alan Turing (1937) to serve as an idealized model for mathematical calculation. A Turing machine having of a line of

IT PRoject Management, What are the benefits of using work breakdown struct...

What are the benefits of using work breakdown structure, Project Management

Production, How useful is production function in production planning?

How useful is production function in production planning?

Brain game, If the first three words are the boys down,what are the last th...

If the first three words are the boys down,what are the last three words??

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd