CSE355 Module 2: Quiz 8
The union of a CFL and a regular language is always a CFL
a. True
b. False - ANS-a. True
If L1 is a CFL and L2 is a CFL, then L1L2 is a CFL
a. True
b.False - ANS-a. True
Any NFA transition diagram can be converted to an equivalent PDA transition diagram by
rewriting every transition labeled with some character (or possibly ε) a to instead be labeled as
a, ε -> ε
a. True
b. False - ANS-a. True
Must it always be the case that the input alphabet, is a subset of the stack alphabet?
a. Yes
b. No - ANS-b. No
If a pushdown automaton recognizes some language, then it is context-free
a. True
b. False - ANS-a. True
The class of PDAs which do not utilize the stack (in other words, every transition is of form a, ε
-> ε, and a ∈ Σ) recognizes precisely the regular languages
a. True
b. False
c. False, there are some PDAs that don't use the stack that can recognize non-regular
languages - ANS-a. True
I have a PDA in which no transition pops the stack. What class of languages can such PDAs
recognize? (Choose the most specific answer)
a. Context-free Languages
b. Chomsky Normal Languages
c. Regular Languages
d. Finite Languages - ANS-c. Regular Languages
Suppose that M = (Q, Σ, 𝜞, δ, q0, F) is a PDA. Is it possible for Q, 𝜞, δ, and F to be empty?
(Choose the most specific answer)
a. Only F may be empty
b. None of them can be empty
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Hkane. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.99. You're not tied to anything after your purchase.
