- Computer Science Engineering (CSE)
- Theory of Computation
- Unit 1
- Two strings x and y are indistinguishabl...

Q. |
## Two strings x and y are indistinguishable if: |

A. | δ*(s, x) = δ* (s, y), i.e. the state reached by a DFA M on input x is the same as the state reached by M on input y |

B. | if for every string z Є ∑* either both xz and yz are in language A on ∑* or both xz and yz are not in A |

C. | Both above statements are true |

D. | None of the above |

Answer» C. Both above statements are true |

View all MCQs in:
Theory of Computation

- Let L be any infinite regular language, defined over an alphabet Σ then there exist three strings x, y and z belonging to Σ such that all the strings of the form XY^ n Z for n=1,2,3, … are the words in L called
- Consider the following statements about the context free grammar G = {S - >SS,S - >ab,S ->ba, S - ε} I. G is ambiguous II. G produces all strings with equal number of a’s and b’s III. G can be accepted by a deterministic PDA. Which combination below expresses all the true statements about G?
- The set strings of 0's and 1's with atmost one pair consecutive one's-
- How many strings of length less than 4 contains the language described by the regular expression (x+y)*y(a+ab)*?
- Which of the following strings is not generated by the following grammar? S → SaSbS ε
- A language is represented by a regular expression (a)*(a + ba). Which of the following strings does not belong to the regular set represented by the above expression?
- Let L be a language defined over an alphabet ∑,then the language of strings , defined over ∑, not belonging to L denoted by LC or L. is called :
- Let L={w (0 + 1)* w has even number of 1s}, i.e. L is the set of all bit strings with even number of 1s. Which one of the regular expression below represents L?
- The regular expression have all strings in which any number of 0’s is followed by any number of 1’s followed by any number of 2’s is :
- Which of the following are decidable? 1) Whether the intersection of two regular language is infinite. 2) Whether a given context free language is regular. 3) Whether two push down automata accept the same language. 4) Whether a given grammar is context free.

Login to Continue

It will take less than 2 minutes

Report MCQ