Automata Theory and Formal Language

The following are phases of C++ Programs except

• Process

An algorithms to shampoo your hair.

• rinse, lather, repeat

Which of the following will not be accepted by the following DFA?

• ababaabaa

Is a finite set of symbols called the alphabet.

• Σ

Terminal symbols

• a & b

Number of final state require to accept in minimal finite automata.

• None of the mentioned

A set has n elements, then the number of elements in its power set is?

• 2n
• 2 ^ n
• None of the choices
• 2n-1

Increasing accuracy, or precision

• Minimizing False Positives

|-* is the _____ closure of |-

• transitive and reflexive

The string acde is accepted by this regular expression.

• a+b+c+d+
• a+b+c+d+e*
• a*b*c*a*d*
• a*b*c*a*d*e+

The language L contains all strings over the alphabet {a,b} that begin with and end with

• a,b

Noam Chomsky gave a mathematical model in which is effective for writing computer languages.

• 1956

Connected graphs have components.

• True
• False

Having the initial state as a final state, give the deterministic finite state automaton that accepts the regular expression.

• ((a.b)+c)*

A finite number of states.

• Q

Unconsumed input

• w

According to what concept is CFL a superset of RL?

• Chomsky Hierarchy
• Chomsky Normal Form
• Backus-Naur Form
• None of the given choices

If L1 and L2 are regular sets then intersection of these two will be.

• Regular

A PDA accepts a string when, after reading the entire string, the PDA is in a final state.

• TRUE

For every CFL, G, there exists a PDA M such that L(G) = L(M) and vice versa

• TRUE

A 2-Tape Turing Machine ___________________.

• can infer that recursive languages are closed under union
• can show that recursive languages are closed under union
• has two outputs
• has two inputs

The relationship between recursive and recursively enumerable languages is ________________.

• ∈
• ⊂
• ∉
• ⊃

The entity which generate Language is termed as regular languages.

• FALSE

A set of strings of a's and b's of any length including the null string. So L= { ε, a, b, aa , ab , bb , ba, aaa.......}, the regular

• (a+b)*

It is a unary operator on a set of symbols or strings, that gives the infinite set of all possible strings of all possible lengths.

• Σ *

Regular expression Φ* is equivalent to.

• ϵ

“Whenever H holds, C follows” can also be said as _______.

• H → ε and ε → C
• H → C
• C → H
• ε → H and C → ε

The difference between DFA and NFA

• DFA is where you get your passport while NFA is where you get your cheap rice
• NFA can exist in only one state at a given time while DFA can exist in multiple states
• DFA can exist in only one state at a given time while NFA can exist in multiple states
• DFA is also an NFA

* Starts with the starting symbol S. It goes down to tree leaves using productions.

• Top-Down Approach

Labeled by a terminal symbol or ε.

• Leaves

A conceptual design for a machine consisting of a Mill, Store, Printer, and Readers.

• Analytic Engine

Every set is a / an ________________ of itself.

• None of the choices
• Complement
• Proper Subset
• Improper Subset

According to the 5-tuple representation i.e. FA= {Q, ∑, δ, q, F} Statement 1: q ϵ Q'; Statement 2: FϵQ

• Statement 1 is false, Statement 2 is true

The difference between regular expressions and finite automata is _____________.

• that automata are more program syntax-like while regular expression are more machine-like
• |regular expression| - |finite automata| = |Turing Machine| because you can only get the difference by computing for their respective lengths
• that regular expressions are more program syntax-like while automata are more machine-like
• {regular expression} - {finite automata} = { } because they are sets and they are equivalent

Increasing coverage, or recall.

• Minimizing False Negatives

A Finite Automaton with null moves (FA-ε) does transit not only after giving input from the alphabet set but also without any input symbol. This transition without input is called a

• Null Move

The complement of an infinite language is necessarily finite.

• FALSE

are parameterized statement, they are true or false depending on the values of their parameters.

• predicates

The string abe is accepted by this regular expression.

• a*b*c*a*d*
• a+b+c+d+e*
• a*b*c*a*d*e+
• a+b+c+d+

Set of final or accepting states.

• F

A Moore machine can be described by a tuple.

• 6

Set of all tape symbols

• Γ

The first mechanical calculator using gears for calculation developed in 1642.

• Pascaline

The recursive inference procedure determines that string w is in the language of the variable A, A being the starting variable.

• TRUE

A set of final state/states of Q (F⊆Q).

• F

All trees contain loops.

• True
• False

A transition function δ : Q × (Σ ∪ {ε}) → 2Q.

• δ

The theory of formal languages finds its applicability extensively in the fields of Computer Science. gave a mathematical model of grammar in which is effective for writing computer languages.

• Noam Chomsky, 1956

Is the initial state from where any input is processed (q0 ∈ Q).

• q0

Global Positioning System (GPS) calculates latitude and longitude from satellite signals.

• True

A parsing that starts from the top with the start-symbol and derives a string using a parsetree.

• top-down parser

Finite set of states.

• Q

Any production rule in the form A → B where A, B ∈ Non-terminal is called.

• Unit Production

Which among the following is the correct option for the given grammar? G->X111|G1,X->X0|00.

• {0a1b|a=2,b=3}

IT generate recursively enumerable languages. The productions have no restrictions and phase structure grammar including all formal grammars. They generate the languages that are recognized by a Turing machine.

• Type-0 grammars

If A has m elements and B has n elements, then A x B has elements?

• m - n
• m + n
• 2n
• m x n

If we can successfully and ly stimulate a TM with storage by two standard TMs, then ______________________

• we have already shown that the two are equivalent

“If H then ” is also the same as saying _______.

• “If H then C else do nothing”
• “If C then H”
• “If H then C else {}”
• “C if H”

A nested if-then statement is one of these:

• If w then x if y then z
• If w if x then y then z
• If w then if x then y else z
• All of the choices are examples of nestedness

Finite Automata all regular languages and only regular languages.

• Accept

__ is a set of final state/states of Q (F ⊆ Q).

• F

__ is the transition function where δ: Q × Σ → Q.

• δ

Leibniz introduced binary notation of calculation.

• FALSE

Increasing accuracy, or precision.

• Minimizing False Positives

Finite set of states

• Q

What can be said about CFLs?

• It is closed under ~
• It is closed under ∩
• All of the given choices
• It is closed under •

Let the class of language accepted by finite state machine be L1 and the class of languages represented by regular expressions be L2 then.

• L1=L2

The __________ of a Turing machine depends on the current state of finite control and the tape symbol present in the input tape.

• single move

If A →* ε, then we can say that:

• A is not generating
• A is not reachable
• A is nullable
• A is not generally useful

The of a Turing machine depends on the current state of finite control and the tape symbol present in the input tape.

• Single Move

Start symbol, S ∈ N

• S

If we can successfully and correctly stimulate a TM with storage by two standard TMs, then ______________________.

• None of the choices
• we have already shown that the TM with storage is at least twice as powerful as one standard TM
• we have already shown that the two are equivalent
• we have already shown that one standard TM is half as powerful as the TM with storage

A general purpose, programmable, information processor with input and output.

• computer

The _____ of two sets A and B is the set containing those elements which are elements of A or elements of B.

• union

If L1 and L2 are regular sets then intersection of these two will be

• Regular

A compact textual representation of a set of strings representing a language.

• Regular Expressions

Given that the language L = {ε}, is L empty?

• None of the given choices
• No, because the language has an empty symbol
• Definitely, because ε is an empty symbol
• This is a case of apples and oranges, you really can't compare!

Transition function

• δ

Is to be applied to show that certain languages are not regular. It should never be used to show a language is regular.

• Pumping Lemma

For a regular expression 'a', we can construct the following FA:

• TRUE

Which of the following Set Operations produces the set that contains everything that is in Set A and in Set B?

• Complement
• union
• Intersection
• Set Difference

A grammar G is ambiguous if there is a word w Î L(G) having are least two different parse trees.

• TRUE

In _____ Allan M. Turing proposed the Turing machine as a model of "any possible computation".

• 1936

The body of a production in CFG is composed of:

• a string of terminals only
• none of the choices given because a CFG production does not have a body
• a string of non-terminals only
• a string of terminals and non-terminals

The empty set is always a subset of any set.

• True
• False

Checking whether there is a matching parenthesis in a computer code can be done by a ______________.

• regular expression
• automatically by a very patient debugger
• context-free language
• context-free grammar

If Σ2 is {00, 01, 10, 11}, then Σ =

• {0, 1}
• {false, true}
• {true, false}
• {F, T}

A set of terminals where N ∩ T = NULL.

• T

Computer science has roots in two fields :

• Mathematics

The unconsumed input

• w

A set of strings of a's and b's of any length including the null string. So L= { ε, a, b, aa , ab , bb , ba, aaa.......}, the regular expression is.

• (a+b)*

IT generate recursively enumerable languages. The productions have no restrictions and phase structure grammar including all formal grammars.

• Type-0 grammars

What can be said about undecidable problems?

• They are definitely recursive
• They are surely iterative
• They are not recursive
• They are not iterative

A finite set of states.

• Q

Which among the following cannot be accepted by a regular grammar?

• L is a set of 0n1n

Context-free grammars are more expressive than finite automata; if a language L is by a finite automata then L can be by a context-free grammar.

• Accepted, Ignored

“C if H” is also the same as saying _______.

• “If H then ”
• “If C then H”
• “If H then C else {}”
• “If H then C else do nothing”

Finite set of input alphabets.

• Σ

Elimination of productions and symbols is called simplification of CFGs. Simplification essentially comprises of the following steps:

• Reduction of CFG

An English like abbreviations representing elementary computer operations.

• Assembly Language

It starts from the top with the start-symbol and derives a string using a parse tree.

• Top-Down Parser

A pushdown automata can be regarded as:

• a ε-NFA with a stack
• a DFA with a FILO queue
• a NFA with a stack
• a DFA with FIFO queue

A transition function: Q × (Σ∪{ε}) × S × Q × S*.

• δ

The CFG "S → (S) | SS | ε" accepts:

• the string "<<>><><<>>"
• the string "(((((((((())))))))))"
• the string "((()))(())(())"
• the string "{} { {} } [[]]"

Regular expression Φ* is equivalent to

• ϵ

If R ={(1,1),(2,3),(4,5)}, then the Range of the function is?

• Range R {1,1,4,5}
• Range R {1,2,5}
• Range R = {2,3,4,5}
• Range R = {1,3,5}

A Finite Automaton with null moves (FA-ε) does transit not only after giving input from the alphabet set but also without any input symbol. This transition without input is called a.

• Null Move

A ⊂ B is read as ________________.

• A is less than B
• A is a subset of B
• B is a subset of A
• A is a proper subset of B

Who is the father of modern computer?

• Charles Babbage

JASON can generally be parsed by ______________.

• A C parser
• A CFG
• A Java parser
• A RE

The unconsumed input.

• w

Are ambiguous grammar context free?

• TRUE

Regular sets are closed under union,concatenation and kleene closure.

• TRUE

If A = {3, 4, 6, 8} and

• { 4,6}

Context Free Languages is closed under intersection.

• False
• True

The transition a Push down automaton makes it additionally dependent upon the

• Stack

A DFA can remember a finite amount of information, but a can remember an infinite amount of information.

• PDA

If L is recursively enumerable then ________________.

• none of the choices given is correct
• L is also recursively enumerable
• L is definitely not recursively enumerable
• L may not be recursively enumerable

Context-free grammars are more expressive than finite automata; if a language L is by a finite automata then L can be blank by a context-free grammar.

• Accepted

Z2 uses electricity to convey letters and transmit information quickly in 1844.

• TRUE

What is an ε-NFA?

• It is a DFA where all transitions are ε-transitions
• It is an NFA where all transitions are ε-transitions
• It is a DFA with at least one explicit ε-transition defined
• It is an NFA with at least one explicit ε-transition defined

A finite number of states

• Q

What is the final result after converting the following NFA-ε to NFA without Null move.

• What is the final result after converting the following NFA-ε to NFA without Null move.

The algebraic law of regular expression described by E + E = E is _____________.

• Annihilator
• Identity
• Additive idempotent
• Idempotent

Is a set of final state/states of Q (F ⊆ Q).

• F

The algebraic law of regular expression described by φE = φ = Eφ is _______________.

• Annihilator
• Associative
• Commutative
• Identity

A right-most derivation of a sentential form is one in which rules transforming the are always applied.

• Context

Noam Chomsky gave a mathematical model in ___ which is effective for writing computer languages.

• 1956

What cannot be said about automata theory?

• None of the choices
• Automata theory is the study of abstract computing devices or machines
• Automata theory is used to find out if a problem is computable
• Automata theory answers the fundamental questions in computer science

It generate context-free languages. The productions must be in the form A → γ

• Type-2 grammars

Blank symbol

• Δ

A formal language is a set of strings, each string composed of symbols from a finite set called.

• Alphabet

A string is accepted by a, iff the DFA/NDFA starting at the initial state ends in an after reading the string.

• NDFA

Any production rule in the form A → B where A, B ∈ Non-terminal is called unit production.

• Unit Production

If A = {5,6,7} and B = {7,8,9} then A U B is equal to:

• {5,6,7}
• None of the choices
• {7,8,9}
• {5,6,7,8,9}

Production Rule: aAb->agb belongs to which of the following category?

• Context Sensitive Language

Which of the following statement is false in context of tree terminology?

• Root with no children is called a leaf

Which of the following ways can be done to simplify a CFG?

• Eliminate symbols that are not useful
• Eliminate the ε symbol
• Eliminate productions of the form A → B

A may or may not read an input symbol, but it has to read the top of the stack in every transition.

• PDA

* Starts from tree leaves. It proceeds upward to the root which is the starting symbol S.

• Bottom-Up Approach

The stack contents

• s

Let w = 100011, is w a member of a language of string with equal number of 0s and 1s?

• Yes, because the number of 1s is the same as the number of 0s, which is 3
• It is hard to ascertain because 100011 is 35 in decimal, which is an odd number
• No, because even if the symbols 1 and 0 are of the same number, they are not palindromic
• This is an NP-hard problem

If R = {(1,1),(2,3),(4,5)}, then domain of the function is?

• Dom R = {2,3,4,5}
• Dom R = {1,2,4}
• Dom R {1,3,5}
• Dom R {1,1,4,5}

A __________ of a derivation is a tree in which each internal node is labeled with a nonterminal.

• parse tree

Which among the following is the option for the given grammar? G->X111|G1,X->X0|00

• {0a1b|a=2,b=3}

NP-Hard problems are problems that are...

• Easy (they are called hard so that computer programmers can be paid more)
• intractable
• none of the choices
• hard

The string "0000111" is accepted by _____________.

• the CFG S → 0S1 | A, A → A1 | ε
• the CFG S → 1S0 | A, A → A0 | ε
• the CFG S → 0S1 | A, A → 0A | ε
• none of the choices

An alphabet is any finite set of symbols.

• TRUE

Which of the following statements are for a concept called inherent ambiguity in CFL?

• Every CFG for L is ambiguous

The intersection of sets A and B is expressed as _________________.

• A - B
• A / B
• A x B
• A ∩ B

Non-terminal symbols

• S & A

Some graphs contain cycles.

• True
• False

A PDA machine configuration (p, w, y) can be correctly represented as.

• Current state, Unprocessed input, Stack content

Number of states require to accept string ends with 10.

• 3

The string aaaabbbccaaad is accepted by this regular expression.

• a+b+c+d+
• a*b*c*a*d*e+
• a*b*c*a*d*
• a+b+c+d+e*

A set on non-terminal symbols.

• S & A

The power set of a given set does not contain the set itself.

• True
• False

Given the language L = {ε}, is L empty?

• none of the given choices
• Definitely, because ε is an empty symbol
• No, because the language has an empty symbol
• You can't say

A PDA machine configuration (p, w, y) can be correctly represented as ____________ .

• current state, unprocessed input, stack content

Is the transition function where δ: Q × Σ → Q.

• δ

Recursive : TM that always halt = ________________ : TM that may or may not halt

• iterative
• recursively enumerable
• none of the choices given
• iteratively enumerable

The entity which generate Language is termed as:

• Grammar

Which one is the answer?

• Computer

The first counting machine developed 5000 years ago in the Middle East.

• Abacus

The minimum number of states required to recognize an octal number divisible by 3 are/is.

• 3

A - B will contain elements in?

• B not in A
• A not in B
• Neither A nor B
• Both A and B

An automaton that produces outputs based on current input and/or previous state is called.

• Transducer

Computers are general purpose because they can perform many different tasks.

• TRUE

In the Chomsky Hierarchy:

• Regular Language ⊂ Context-sensitive Language
• Regular Language ⊃ Context-sensitive Language
• Regular Language| • |Context-sensitive Language
• Regular Language = Context-sensitive Language

The initial stack top symbol (I ∈ S)

• I

Empty string

• Σ

An initial state q0 ∈ Q.

• q0

Which of the following statements are correct for a concept called inherent ambiguity in CFL?

• Every CFG for L is ambiguous

Any set that represents the value of the Regular Expression is called a Property set.

• FALSE

How many rational and irrational numbers are possible between 0 and 1?

• 0
• Infinite
• Finite
• 1

All relations are functions

• True
• False

T generate recursively enumerable languages. The productions have no restrictions and phase structure grammar including all formal grammars.

• Type-0 grammars

If a problem can be shown that it belongs to the class of recursively enumerable languages then ______________________.

• It may be solved by any TM
• It may be solved by a special RE
• It may be solved by a special TM
• It may be solved by any RE

One of the first programmable electronic computers in 1945.

• ENIAC

What concept did Alan Turing introduce?

• The concept of programs and programmabilities of problems
• The concept of decidability
• The concept of functions and relations
• The concept of undecidability

What are strings?

• A string is an infinite area of symbols chosen from Σ
• A string is a finite sequence of symbols chosen from Σ
• A string is a finite area of symbols chosen from Σ
• A string is an infinite sequence of symbols chosen from Σ

Circuits in graphs are always simple paths.

• True
• False

A of a derivation is a tree in which each internal node is labeled with a nonterminal.

• Parse Tree

The stack contents.

• s

A finite set of states

• Q

The cardinality of the union of two disjoint sets is less than the sum of the cardinality of the given sets.

• True
• False

Language may be derived from other strings using the productions in a grammar.

• FALSE

Is used to derive a string using the production rules of a grammar.

• Production

A new symbol is added at the top.

• Push

In mathematical notation, the symbol → means...

• implication
• an element of
• not an element of
• assignment statement

S → aAb, aA →aaAb, A→ε

• P

Starting state

• q0

A set of accepting states (F ∈ Q).

• F

The start symbol.

• S

A formal language is a set of strings, each string composed of symbols from a finite set called

• alphabet

The tape head is positioned at one of the tape cells for scanning the input symbol from the input tape and initially the tape head points at the left most cell of the input tape.

• TRUE

An order rooted tree that graphically represents the semantic information a string derived from a context-free grammar.

• Derivation tree

A set of rules, P: N → (N U T)*, it does have any right context or left context.

• P

The transition a Push down automaton makes it additionally dependent upon the _____.

• stack

Set of final or accepting states

• F

An ε-NFA with a stack is also regarded as:

• A CFG
• A FSA
• A PDA
• A RE

A good regular expression for any valid whole number is ______________.

• [0-9]*
• [0-9]*[0-9]*
• [0-9]+
• [0-9]+[0-9]*

An indirect way of building a CFG is to _____________

• build a regular expression and then construct a PDA from it, and then construct CDF from it
• You can only build a CFG directly
• build a PDA and then construct a CFG from it
• none of the given choices

Empty set is a/an ________________.

• Infinite set
• Finite set
• Invalid set
• None of the choices

A language accepted by Deterministic Push down automata is closed under which of the following?

• complement

What is a grammar?

• How a sentence should be constructed to avoid syntax error
• "Them cowboys is dumb!" is an example of a wrong grammar
• "We ain't gonna make mistakes" is an example of correct grammar
• A device that enumerates the sentences of a language

What is automata theory?

• To answer the fundamental questions in computer science
• All of the choices
• To find out if a problem is computable
• Study of abstract computing devices or machines

A regular expression consisting of a finite set of grammar rules is a quadruple.

• FALSE

A DPDA is a PDA in which.

• No state p has two outgoing transitions

A DFA can remember a finite amount of information, but a ____ can remember an infinite amount of information.

• PDA

An initial state q0 ∈ Q

• q0

A set of accepting states (F ∈ Q)

• F

A PDA is already in its accept state if:

• and only if it is both in the final state and the stack is empty
• none of the given choices
• it is either in the final state or the stack is empty
• it has no more input to process

The symbol used for the empty string is ____________.

• ε
• φ
• a blank
• ψ

A pushdown automaton is a way to implement a context-free grammar in a similar way to design DFA for a regular grammar.

• TRUE

Turing hypothesis believed that a function is said to be computable if and only if it can be computed by a Turing machine.

• FALSE

A may or may not read an input symbol, but it has to read the top of the stack in every transition

• PDA

Every context free grammar can be transformed into an equvalent non deterministic push down automata.

• TRUE

For bottom-up parsing, a PDA has the following four types of transitions:

• Push the current input symbol into the stack., Replace the right‑hand side of a production at the top of the stack with its left‑hand side. , If the top of the stack element matches with the current input symbol, pop it. , If the input string is fully read and only if the start symbol 'S' remains in the stack, pop it and go to the final state .

It starts from the bottom with the string and comes to the start symbol using a parse tree.

• Bottom-Up Parser

For every pair of regular expressions R and S, the languages denoted by R(SR)* and (RS)*R are the same.

• TRUE

__ is the initial state from where any input is processed (q0 ∈ Q).

• q0

The top symbol is read and removed.

• Pop

__ is a finite set of symbols called the alphabet.

• Σ

* Starts from tree leaves. It proceeds upward to the root which is the starting symbol S

• bottom-up approach

A language is regular if and only if.

• Accepted by DFA

What is an undecidable problem?

• When a TM cannot make a decision on an instance of the problem
• When a CFG cannot make a decision on an instance of the problem
• When a PDA cannot make a decision on an instance of the problem
• When a RE cannot make a decision on an instance of the problem

NFA means:

• Nondeterministic Finite Automaton
• Nondeterministic Final Automaton
• Nondifferentiable Final Automaton
• Nondifferential Finite Automaton

The number of elements in the set for the Language L={xϵ(∑r) *|length if x is at most 2} and ∑={0,1} is

• 7

Finite set of input alphabets

• Σ

______ is used to derive a string using the production rules of a grammar.

• Parsing

Identify the modeling recognition of the word "then"

• Start State

Which of the following statements is true about NPDA, DPDA, and RL?

• RL • DPDA • NPDA
• RL* • DPDA* • NPDA*
• RL ⊃ DPDA ⊃ NPDA
• RL ⊂ DPDA ⊂ NPDA

What is a language?

• A way to communicate with other humans
• A collection of finite-length sentences that were constructed from a finite set of symbols
• A code that you use when writing a computer program
• English, Filipino and Valyrian are examples of a language

|-* is the closure of |-

• Transitive and Reflexive

{Q, Σ, q0, F, δ, Q × Σ → Q} is…

• An NFA
• Either DFA or NFA
• There is no such tuple
• A DFA

Who is the father of modern computer science?

• Noam Chomsky
• Alan Turing
• Steve Jobs
• Bill Gates

A stack symbols

• Σ

A DFA is defined ____________________.

• as Department of Finite Automaton
• by a 5-tuple which is {Q, Σ, q0, F, δ}
• by a 6-tuple which is {Q, Σ, q0, F, δ, Q × Σ → Q}
• as Department of Foreign Affairs

It process information in their efforts to eat, survive, and reproduce.

• Living Organisms

If A = {0,2) and B = {1,3), then Cartesian product is?

• none of the choices
• A x B not equal B x A
• A x B = B x A
• is not possible

A' will contain how many elements from the original set A?

Which among the following is not a part of the Context free grammar tuple?

• End SymbolCorre

In ____ Allan M. Turing proposed the Turing machine as a model of "any possible computation".

• 1936

The commutativity property of set operations states that the union of any set with same set is the set itself.

• True
• False

What is a Universal TM?

• a TM that stimulates another TM
• A TM that can solve all problems
• A TM that can solve all undecidable problems
• a Universal TM does not exist

Labeled by a non-terminal symbol.

• Vertex

It refers to the measure of the number of times the tape moves when the machine is initialized for some input symbols and the space complexity is the number of cells of the tape written.

• Time Complexity

There are 5 tuples in finite state machine.

• TRUE

The initial state (q0 ∈ Q)

• q0

The PDA has infinite memory and access in _____ order and the finite automata has ____ memory.

• LIFO, finite

A DFA is represented by digraphs called.

• State Diagram

A DPDA is a PDA in which

• No state p has two outgoing transitions

A sub-tree of a derivation tree/parse tree such that either all of its children are in the sub-tree or none of them are in the

• Partial Derivation Tree, Sub-Tree

Is a finite set of states.

• Q

Noam Chomsky gave a mathematical model in _______ which is effective for writing computer languages.

• 1956

What can not be said about CFLs?

• It is closed under ~
• It is closed under —
• All of the given choices
• It is closed under ∩

A good regular expression of a person's name is ______________.

• None of the given choices
• [A-Z][a-z]+
• [A-Z][a-z]?
• [A-Z][a-z]*

A good regular expression for any valid real number using engineering notation is ______________.

• [0-9]+[0-9]*[(E|e)[0-9]+]
• [0-9]*
• [0-9]+[0-9]*[(E|e|∈)[0-9]+]
• [0-9]+

__ is a finite set of states.

• Q

In Allan M. Turing proposed the Turing machine as a model of "any possible computation".

• 1936

What kind of languages does a TM decide?

• regular expression
• context-sensitive
• recursively enumerable
• context-free

For the given Regular expression, the minimum number of terminals required to derive its grammar (011+1)*(01)* is

• 3,6,2,5,4

The initial stack top symbol (I ∈ S).

• I

The basic model of a Turing machine consists of _______ and _______ , in which the finite control has finite set of states and the transition between the states.

• finite control, input tape

How many sets belong to the power set of A = {a,b,c,d}?

• 4
• 8
• 7
• 16

Context-free grammars are more expressive than finite automata; if a language L is _____ by a finite automata then L can be _______ by a context-free grammar.

• accepted, generated

challenged the mathematical community to find an infallible, mechanical method for constructing and checking truth of mathematical statements.

• David Hilbert

The stack content

• s

An example string w of a language L characterized by equal number of As and Bs is _______________.

• BABAE
• ABABA
• ABBBAA
• ALIBABA

A finite set of input symbols.

• Σ

In words, H → C means…

• Whenever H holds, C follows
• Whenever H does not follow, C does not follow either
• Whenever H is true, then it becomes C
• Whenever H, then it becomes C

A symbol X is reachable _________________________.

• if S → aXβ
• if X →* w, for some w ∈ Σ
• if X → w, for some w ∈ Σ
• if S →* aXβ

All functions are relations

• True
• False

Unconsumed input.

• w

Which of the following is a not a part of 5-tuple finite automata?

• Output Alphabet

Given the productions S → αXβ, X → a, ___________________.

• X is not reachable nor generating
• X is reachable but not generating
• X is useful
• X is not reachable but is generating

A transition function: Q × (Σ∪{ε}) × S × Q × S*

• δ

A PDA machine configuration (p, w, y) can be ly represented as ____________

• current state, unprocessed input, stack content

A _____ may or may not read an input symbol, but it has to read the top of the stack in every transition

• PDA

Labeled by the start symbol.

• Root Vertex

For every CFL, G, there exists a PDA M such that L(G) = L(M) and vice versa.

• TRUE

The union of sets A and B is expressed as?

• A U B
• A - B
• A / B
• A x B