Linked Questions

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votes
1answer
18 views

How can I prove that the accepted language of a given DFA or NFA or REGEX is equivalent to a given language

I found this How do I verify that a DFA is equivalent to a NFA? but as it states it is not really a good question more of how can I check myself during an exam. Because as you might know to do this by ...
0
votes
1answer
24 views

A grammar for my context free language {xy | x, y ∈ {a, b} ∗ , |x| =|y| , x != y}

This question is given as an exercise to me . I took a look at the solution given by the instructor which is not the same as my solution . So I thought it would be wise to ask it here considering ...
-1
votes
1answer
30 views

What is the language generated by this grammar?

I'm struggling to find the language generated by the following grammar: Any help would be appreciated.
1
vote
2answers
53 views

Is my grammar correct and context free?

I have this language $L = \{a^{n}b^{3n}c^{2m} : m,n \ge 1\}$. I have to determine a free context grammar that generates L. Looks easy BUT i have a question about the grammar I found. First things ...
0
votes
1answer
45 views

Language to regex

Let A={a,b}. So the question is to write regular expression such that L(r) which consists of all words. My answer is this: L(r)= (a+b)* a* b* (a+b)* Is this ...
2
votes
1answer
180 views

Proving that L(G) is the language defined by the CFG G

I have a context-free grammar defined by the production S: S → aSbS ∣ bSaS ∣ ε I need to prove that the CFG "G" can be defined as a language L(G) where L(G) = {w ∈ {a, b}∗ ∶ na(w) = nb(w)}. ...
-1
votes
1answer
60 views

Find the language from a context free grammar

I am having trouble determining the language from a given context free grammar. I've been given a hint that there are 2 parts to the language but can't figure either out. $$G= (\{S,A,B,C,D,E,Z\},(0,...
2
votes
2answers
357 views

Proof for BFS and DFS equivalence

I'm trying to prove (by induction) that BFS in equivalent to DFS, in the sense that they return the same set of visited nodes, but I'm stuck in the middle of some of the cases. Let $G$ be a directed ...
2
votes
1answer
93 views

How to produce a context free grammar for this language?

I've already attempted it but I am finding it difficult to understand if this is correct. give a context free grammar for the following: $$ \{p^{3m+n}q^nr^2p^m\mid m,n\ge 0 \}$$ The answer i've ...
2
votes
0answers
240 views

Context-sensitive grammar for language $L = \left\{ww \mid w \in \left\{a,b\right\}^* \right\}$ [duplicate]

Find a context-sensitive grammar for language $L = \left\{ww \mid w \in \left\{a,b\right\}^* \right\}$ where $L \in DCSL \setminus CFL$. I find this task from old exam but there is no solution. I try ...
2
votes
1answer
83 views

Proving $L = \{ w : w \neq w^R \}$ over $\Sigma = \{0,1\}$ is CFL

I'm trying to prove $L = \{ w : w \neq w^R \}$ over $\Sigma = \{0,1\}$ is CFL. Define $G = ({S,T}, \Sigma, R, S)$ where $R = S \to 0S0|1S1|0T1|1T0, \; T \to 0T|1T|\varepsilon$. Now I want to show ...
0
votes
2answers
158 views

Removing epsilon transition from the grammar. What's the difference between accepting languages?

I want to remove the epsilon transition from following grammar: \begin{eqnarray} S & \rightarrow & A | B \\ A & \rightarrow & \epsilon \\ B & \rightarrow & aBa \\ B & \...
1
vote
3answers
648 views

Context-free grammar for binary words

I am supposed to create CFG for this languague: $L= \{w : w \in \{a, b\}^*, |w_b| = 3k, k \geq 0 \}$ where $|w_b|$ is count of terminals $b$ in $w$. For example: aa - OK, no 'b' abb - wrong, only ...
0
votes
0answers
92 views

Does this grammar generate regular language?

$S \rightarrow AB$ $A \rightarrow aA \mid bA \mid \epsilon$ $B \rightarrow aBb \mid \epsilon$ Does this grammar generate regular language? According to me this grammar generates language of the ...
0
votes
2answers
392 views

Regular expression $(a^{*}b^{*})^{*} = \left( a+b \right)^{*}$ proof

Im having a lot of trouble proving that for the Regular expression $R_{1} = \left( a^{*} b^{*} \right)^{*}$ and $R_{2} = \left( a+b \right)^{*}$ that $L \left( R_{1} \right) = L \left( R_{2} \right)$. ...

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