Login
Register
@
Dark Mode
Profile
Edit my Profile
Messages
My favorites
Register
Activity
Q&A
Questions
Unanswered
Tags
Subjects
Users
Ask
Previous Years
Blogs
New Blog
Exams
Dark Mode
Michael Sipser Edition 3 Exercise 4 Question 24 (Page No. 212)
admin
asked
in
Theory of Computation
Oct 17, 2019
485
views
0
votes
0
votes
A useless state in a pushdown automaton is never entered on any input string. Consider the problem of determining whether a pushdown automaton has any useless states. Formulate this problem as a language and show that it is decidable.
michael-sipser
theory-of-computation
pushdown-automata
decidability
proof
admin
asked
in
Theory of Computation
Oct 17, 2019
by
admin
485
views
answer
comment
Follow
share this
share
1 comment
by
Joey
commented
Aug 6, 2020
reply
Follow
share this
Wouldn't a simple directed graph representation of the states of the PDA along with the transitions, and a DFS/BFS on that be sufficient?
0
0
Please
log in
or
register
to add a comment.
Please
log in
or
register
to answer this question.
0
Answers
← Previous
Next →
← Previous in category
Next in category →
Related questions
1
vote
1
vote
2
answers
1
admin
asked
in
Theory of Computation
Oct 20, 2019
561
views
Michael Sipser Edition 3 Exercise 5 Question 33 (Page No. 241)
Consider the problem of determining whether a $PDA$ accepts some string of the form $\{ww \mid w \in \{0,1\}^{\ast} \}$ . Use the computation history method to show that this problem is undecidable.
admin
asked
in
Theory of Computation
Oct 20, 2019
by
admin
561
views
michael-sipser
theory-of-computation
pushdown-automata
decidability
proof
1
vote
1
vote
0
answers
2
admin
asked
in
Theory of Computation
Oct 17, 2019
450
views
Michael Sipser Edition 3 Exercise 4 Question 31 (Page No. 212)
Say that a variable $A$ in $CFL\: G$ is usable if it appears in some derivation of some string $w \in G$. Given a $CFG\: G$ and a variable $A$, consider the problem of testing whether $A$ is usable. Formulate this problem as a language and show that it is decidable.
admin
asked
in
Theory of Computation
Oct 17, 2019
by
admin
450
views
michael-sipser
theory-of-computation
context-free-language
context-free-grammar
decidability
proof
0
votes
0
votes
0
answers
3
admin
asked
in
Theory of Computation
Oct 17, 2019
309
views
Michael Sipser Edition 3 Exercise 4 Question 30 (Page No. 212)
Let $A$ be a Turing-recognizable language consisting of descriptions of Turing machines, $\{ \langle M_{1}\rangle,\langle M_{2}\rangle,\dots\}$, where every $M_{i}$ is a decider. Prove that some decidable language $D$ is not ... $A$. (Hint: You may find it helpful to consider an enumerator for $A$.)
admin
asked
in
Theory of Computation
Oct 17, 2019
by
admin
309
views
michael-sipser
theory-of-computation
turing-machine
recursive-and-recursively-enumerable-languages
decidability
proof
0
votes
0
votes
0
answers
4
admin
asked
in
Theory of Computation
Oct 17, 2019
251
views
Michael Sipser Edition 3 Exercise 4 Question 29 (Page No. 212)
Let $C_{CFG} = \{\langle G, k \rangle \mid \text{ G is a CFG and L(G) contains exactly $k$ strings where $k \geq 0$ or $k = \infty$}\}$. Show that $C_{CFG}$ is decidable.
admin
asked
in
Theory of Computation
Oct 17, 2019
by
admin
251
views
michael-sipser
theory-of-computation
context-free-grammar
decidability
proof
Subscribe to GATE CSE 2024 Test Series
Subscribe to GO Classes for GATE CSE 2024
Quick search syntax
tags
tag:apple
author
user:martin
title
title:apple
content
content:apple
exclude
-tag:apple
force match
+apple
views
views:100
score
score:10
answers
answers:2
is accepted
isaccepted:true
is closed
isclosed:true
Recent Posts
Post GATE 2024 Guidance [Counseling tips and resources]
GATE CSE 2024 Result Responses
[Project Contest] Pytorch backend support for MLCommons Cpp Inference implementation
Participating in MLCommons Inference v4.0 submission (deadline is February 23 12pm IST)
IIITH PGEE 2024 Test Series by GO Classes
Subjects
All categories
General Aptitude
(3.5k)
Engineering Mathematics
(10.4k)
Digital Logic
(3.6k)
Programming and DS
(6.2k)
Algorithms
(4.8k)
Theory of Computation
(6.9k)
Compiler Design
(2.5k)
Operating System
(5.2k)
Databases
(4.8k)
CO and Architecture
(4.0k)
Computer Networks
(4.9k)
Artificial Intelligence
(79)
Machine Learning
(48)
Data Mining and Warehousing
(25)
Non GATE
(1.4k)
Others
(2.7k)
Admissions
(684)
Exam Queries
(1.6k)
Tier 1 Placement Questions
(17)
Job Queries
(80)
Projects
(11)
Unknown Category
(870)
64.3k
questions
77.9k
answers
244k
comments
80.0k
users
Recent Blog Comments
category ?
Hi @Arjun sir, I have obtained a score of 591 in ...
download here
Can you please tell about IIT-H mtech CSE self...
Please add your admission queries here:...
Twitter
WhatsApp
Facebook
Reddit
LinkedIn
Email
Link Copied!
Copy