Stack Overflow
Stack Overflow

Questions tagged [pushdown-automaton]

A pushdown automaton (PDA) is a finite-state automaton with added stack based memory. It is a mathematical description of an algorithm for parsing context-free languages.

PDAs extend finite automata via a stack-based memory, and transitions can push/pop symbols to/from the stack. Deterministic PDAs (ones for which there exists only one legal transition at any time) are strictly weaker than non-deterministic ones; such is not the case for finite automata (PDAs are more powerful) or Turing machines (PDAs are weaker).

186 questions
0
votes
1 answer

CFG to PDA (Context free grammar to Push Down Automata)

How can I convert the next CFG to a PDA? S-> abScB | e B-> bB | b
user2880113
  • 345
  • 1
  • 5
  • 13
0
votes
1 answer

What does this notation mean in a pushdown automaton?

My teacher uses weird formatting for PDA, can anybody explain this notation to me The transition function is given as: [q,a,λ, s,B] [s,a,λ,s,λ] [s,b,B,s,λ] Q={q,s} and inputs {a,b} stack {B}, final state F={s} M={Q, E, stack, transition function,…
user103421
  • 1
  • 1
0
votes
1 answer

How do you obtain transition relation of a PDA?

I know how to figure out the start state, accepting state, input alphabet, and all that stuff. But how do you develop thetransition relation of a PDA? For an FSM, (q0,a),q1) means if you start at q0 and get an a, you transition to q1. But what does…
Bryan
  • 2,951
  • 11
  • 59
  • 101
0
votes
2 answers

Formal description of PDA

I remember how to do a formal description of an FSM, but doing one for a PDA looks a little different. Can anyone help explain the circled part? I normally take good notes, but can't seem to find anything on this in my notebook or anywhere else. Any…
Bryan
  • 2,951
  • 11
  • 59
  • 101
0
votes
1 answer

Stuck on a Pushdown Automaton

I'm stuck on a PDA question. The question is as follows: Find push-down automata for the following languages: L={xcy : x, y ∈ (a+b)*, y is not the reverse of x, c is literal} I've built the following machine: https://i.stack.imgur.com/ZqBkW.jpg My…
connorbode
  • 3,015
  • 1
  • 28
  • 31
0
votes
2 answers

Construction of push down automaton from context free grammar

From this section of the Wiki article on PDA, I've got a rough idea on the construction process of a PDA from a given CFG. What this article doesn't make clear is the step required when there are multiple production rules for a single…
dibyendu
  • 515
  • 1
  • 5
  • 16
0
votes
1 answer

Understanding Push Down Automata

I do not understand the arrows in the PDA graph... I have a PDA that accepts all strings with parentheses nested like ((((())))), (()), ((())) etc. It has two states where the first state has an arrow that loops and the behavor of this is described…
rablentain
  • 6,641
  • 13
  • 50
  • 91
0
votes
1 answer

How do I implement pushdown automaton in C#?

I want to code this for PDA. How would I do that in C#? a^nbc^n (n>=0)
ozkank
  • 1,464
  • 7
  • 32
  • 52
0
votes
2 answers

A Decidability Question

Can there be an NFA that decides on real numbers ?
Marigi Maskere
  • 39
  • 1
  • 3
0
votes
2 answers

How to identify Web request from PDA/Desktop/Server?

I would like to know if is possible to identify (with JAVA) the kind of computer used to make a request, for example: Server, desktop, PDA (tablet,cellphone,etc)? Thank you!
user2069668
  • 91
  • 8
0
votes
0 answers

android how to list files from other device

i have another pda device. android phone and pda are connected to same wireless router. i can read files from pda if i know the filename. Now there is a folder called "reports" on pda. i need to show all files in report folder so user clicks on…
Rain
  • 85
  • 11
0
votes
0 answers

ALGORITHM to simulate any Deterministic Pushdown Automata (DPDA)

how to write a program that can model any Deterministic Pushdown Automata (DPDA) the user should enter number of states, transition functions, input symbols the program should model the pda requested for and test for the acceptance or rejection of…
Tom Phil
  • 1
0
votes
2 answers

How to develop application for CASIO DTX30 on .Net?

How to develop application for CASIO DTX30 on .Net ?
shrestha2lt8
  • 305
  • 1
  • 9
0
votes
1 answer

Understanding details in Pushdown Automaton (PDA)

I've recently been set a task to create a Pushdown Automaton that is based on a Finite Automaton that I created beforehand. (I didn't actually do it successfully, which is why I was given a working copy by my tutor) I'm having trouble understand a…
user1191118
  • 1
  • 1
0
votes
1 answer

Why is this not CFG?

Though this is a repitition of this, I talking in terms of designing a PDA. Now, I know I'm wrong, because this is a well publicised example, but where did I go wrong in the PDA design below? I want to accept language {a^n b^n c^n: n>=0} I push two…
nimbudew
  • 958
  • 11
  • 28
1 2 3
…
12
13