Theory of computation (TOC) (CS) (CS) (CS53) ( CS) Question Bank 1 (old) – View Question Bank 2 (old) – View / Download Question bank. Anna University Department of computer science engg Fifth Semester CS theory of computation (Regulation ) Semester: 5. Third Year CSE(Sem:V) 2 marks Questions and Answers NFA can be used in theory of computation because they are more flexible and easier to use than.
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How can a TM acts as a generating device?
Finally the productions are: Then L is not a regular language. The left move is: Computer scientists describes the programming languages by a notation called Backus- Naur Form. Depending on the state and symbol scannedthe device changes stateprints a new symbol and moves its tapehead in one of the 2k directions, either positively or negatively qnswers one of the k-axes.
Text editors and lexical analyzers are designed as finite state systems. A lexical analyzer scans the symbols of a program to locate strings corresponding to identifiers, constants etc, and it has to remember limited amount of information.
The recursive sets include languages accepted by at least one TM that halts on all inputs.
Why are switching circuits called as finite state systems? A k-head TM has some k heads.
Language is a set of valid strings from some alphabet. Give examples of decidable problems. If L is an infinite language in ,then there is a finite subset of L in. That is a G string is in L G if:. On a single move depending on the state of finite control and symbol scanned by each of tape heads ,the machine can change state print a new symbol on each cells scanned by tape head, move each of its tape head independently one cell to the left or right or remain stationary. The two notations for specifying formal languages are: The finite control FC stores a limited amount of information.
What is the basic difference between 2-way FA and TM? Transition diagram is a directed graph in which the vertices of the graph correspond to the states of FA. In one move, the heads may each move independently answerx or right or remain stationary. The notion of computable function can be thheory with the class of partial recursive functions is known as Church-hypothesis or Church-Turing thesis. For eg identifier can be expressed as a regular expression.
Given any TM M and an input string w, does M halt on w? So we require a PDA ,a machine that can count without limit. There is a unique transition on each input symbol. It has an infinite tape divided into cells ,each cell holding one symbol. Prints a symbol on the tape cell scanned, replacing what was written there. The most obvious way to do this is to treat the entire nonblank portion of the initial tape as inputand to treat the entire blank portion of the tape when the machine halts as output.
Turing machine can change symbols on its tapewhereas the FA cannot change symbols on tape. The Turing machine is equivalent in computing power to the digital computer. The class of regular sets are closed under complementation, substitution, homomorphism and inverse homomorphism.
CS Theory of computation RJ edition 2 and 16 marks with answers -Unit wise
Grammar or regular expression Generative approach Automaton Recognition approach. The language accepted by M is: Hence B is useless symbol and remove B from all productions. In 2-way infinite tape TM, the tape is infinite in both directions.
What are the components of Finite automaton model? A parser for grammar G is a program gank takes as input a string w and produces as output either a parse tree for w ,if w is a sentence of G or an error message indicating that w is not a sentence of G. Tweet Share Share Share Share. What is a total recursive function and b partial recursive function.
Enumerable means that the strings in the language can be enumerated by the TM. M is a DFSM that. When a recursively enumerable language is said to wth recursive? ID describe the configuration of a PDA at a given instant. CFL are closed under substitutioncomputatin. Is it true that the language accepted by a non-deterministic Turing machine is different from recursively enumerable language? The diagonalization language consists of all strings w such that the TM M. Interpretive Implementation of Programming languages.