Undecidability: Diagonalization and Universal Languages

This quiz contains multiple-choice problems on diagonalization, universal languages, Rice’s theorem and properties.

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According to Rice’s theorem, If P is a non-trivial property, Lp is

Infinite

Decidable

Undecidable

None of the above

For any non-trivial property of __, no general or effective method can decide whether an algorithm computes it with that property.

Partial functions

Piecewise functions

All of the above

None of the above

Which of the following sets are decidable computable functions?

The class of computable functions that are constant, and its complement

The class of indices for computable functions that are total

The class of indices for recursively enumerable sets that are cofinite

All of the above

Which of the following statements are undecidable for a given Turing machine M?

Does M halt on an empty input tape?

Does M halt for any input at all?

Is L(M) regular? Context-free? Turing decidable?

All of the above

The post correspondence problem is

A decidable decision problem

An undecidable decision problem

Not a decision problem

None of the above

According to Rice's theorem, which of the following options is incorrect?: “Let S be a set of language that is non-trivial such that __”

There exists a TM that recognizes the language in S

There exists a TM that recognizes the language not in S

It is undecidable to determine whether the language recognized by an arbitrary Turing machine lies in S or not

All of the above

The difference between PCP and MPCP is that MPCP requires a solution to start with the first string on each list. True or false?

True

False

What does PCP stand for?

Post-correspondence problem

Post-corresponding problem

Pre-correspondence problem

None of the above

Can a modified PCP problem be reduced to PCP?

Yes

No

Consider three decision problems A, B, and C. A is decidable and B is not. Which of the following is a correct option?

C is undecidable if C is reducible to B

C is undecidable if B is reducible to C

C is decidable if A is reducible to C

C is decidable if C is reducible to B’s complement

Decidable is synonymous to

Recursive

Non-recursive

Recognizable

None of the above

Rec-DFA = { | M is a DFA and M recognizes input w}. Rec-DFA is

Undecidable

Decidable

Non finite

None of the above

Which among the following are semi-decidable?

Empty-DFA

Rec-NFA

Infinite-DFA

All of the above

The languages accepted by a Turing machine are called

Recursively enumerable

Recursive

Recursively enumerable and recursive

None of the above

Which among the following are undecidable theories?

The first order theory of Boolean algebra

The first order theory of Euclidean geomentry

The first order theory of hyperbolic geometry

The first order theory of the natural number with addition, multiplication, and equality

Quiz/Test Summary
Title: Undecidability: Diagonalization and Universal Languages
Questions: 15
Contributed by:
Ivan