Automata Midterm 1

Ace your homework & exams now with Quizwiz!

A DFA that accepts any string that ends with 10 will accept which of these strings?

00000010

What is the regular expression for a DFA that accepts 01 as a substring?

1*00*1(0+1)*

String 00110100 will be accepted by a DFA that accepts?

1010 as substring

String 00110010 will be accepted by a DFA that accepts?

1100 as substring

A DFA that accepts only even number of 1s and 0s will accept which of these strings?

11000011

Study of abstract computing devices or machines is known as:

Automata theory

Regular Languages are NOT closed under union operation.

False

True or False: (RS + R)* RS = (RR*S)*

False

How to decide if a string w in language L is accepted by a DFA?

If the DFA ends in an accepting state

When a language is NOT regular?

If we can show that no FA can be built for a language

What is Pigeon Hole Principle?

at least one hole must contain more than one pigeon

If y >= 4, then 2^y >= y^2 is an example of what type of proof:

deductive

A transition from one state to another state without consuming any additional input symbol is known as:

epsilon-transitions

A DFA is defined by 3-tuple:

false

An alphabet is not a finite set of symbols:

false

Regular languages are regular under reunion.

false

When a language is regular?

if we are able to construct a DFA or NFA or epsilon-NFA or regular expression

An intermediate result that we show to prove a larger result is known as:

lemma

If we are able to construct one of the following: DFA or NFA or ε-NFA or regular expression then the language is called:

regular

A language L is accepted by some e-NFA if and only if L is accepted by some DFA.

true

A language L= Ø if and only if the reachability test fails.

true

A language is a collection of sentences of finite length all constructed from a finite alphabet of symbols:

true

An NFA accepts w if there exists at least one path from the start state to an accepting (or final) state that is labeled by w:

true

An NFA is defined by 5-tuple:

true

Explicit epsilon-transitions between different states introduce non-determinism:

true

For every DFA A there exists a regular expression R such that L(R)=L(A).

true

If we introduce ε then the regular expression (01)* + (10)* + 0(10)* + 1(01)* can be simplified to (ε +1)(01)*(ε + 0).

true

L U M = all strings that are either in L or M.

true

Regular Expressions are more like program syntax.

true

Transitions into a dead state are implicit for a NFA.

true

Unix environments heavily use regular expressions.

true

We use the symbol Σ(sigma) to denote an alphabet:

true

ε-closure of a state q, ECLOSE(q), is the set of all states (including itself) that can be reached from q by repeatedly making an arbitrary number of ε-transitions.

true

Empty string is represented by:

ε (epsilon

L = { w | w is a binary string which does not contain two consecutive 0s or two consecutive 1s anywhere}. What is the regular expression for this language?

(01)* + (10)* + 0(10)* + 1(01)*

A containment hierarchy of classes of formal languages is known as:

Chomsky hierarchy

A property that confirms If a set of regular languages are combined using an operator, then the resulting language is also regular is called:

Closure property

The machine that can exist in only one state at any given time is known as:

DFA

A transition from one state to another state without consuming any additional input symbol is known as:

Epsilon transition

Probabilistic models could be viewed as extensions of which state machines?

NFA

The machine that can exist in multiple state at any given time is known as:

NFA

Which of these is great for modeling regular expressions?

NFA

A technique that is used to show a given language is not regular is known as.

Pumping Lemma

How to minimize a DFA?

Remove unreachable states and Identify & condense equivalent states into one


Related study sets

Praxis 5002 Reading & Language Arts

View Set

Computer Organization and Architecture

View Set

Comedy Driving answers (for ticket dismissal)

View Set

RealestateU quizzes (final exam prep)

View Set

GEOGRAPHY: Unit 4B Quiz Study Set

View Set

Physical Science final exam 2019

View Set