Linked Questions

Question: L is a language defined as $\ L = \{1^l | l\in primes\}$ (strings of 1s having a prime length). Show that this is not a regular language ($\ L \notin REG$). You may either use the theory ...

This is a question from a text book that's giving me some trouble. The question is: Determine whether or not this language is regular. Justify your answer. $$L = \{ww : w \in \{a,b\}^* \}$$ I ...

I was trying to approach this proof, after multiple reads and attempts I am getting nowhere. If someone could help me out that would be great. Should I use the pumping lemma, if so how show I start, ...

I know that the language $\{a^m b^n | n\neq m\}$ satisfies the pumping lemma, but it's still not regular (I have to count the # of a's and b's). How can I formally prove it?

My language is the repetition of 0 to a length that's a power of 2: $L = \{ 0^k \ni k=2^n, n \geq 1 \}$ I want to know how to prove that this language is not regular. I have attempted the proof ...

Question: ($B$ and $C$ are languages) $B$ is finite,$C$ isn't regular: Prove/Disprove: $C\cup B$ isn't regular. Thoughts: My intuition says this is true, but I need an idea to prove it. Since I don'...

In general, how can we go about proving that union of two languages as non regular. In this case, the individual languages can be proved as non regular using pumping lemma. How can we apply pumping ...

Let $\Sigma = \{0,1\}$. For every word $w \in \Sigma^*$, let $|w|_0$ and $|w|_1$ denote the count of 0's and 1's, respectively, in $w$. Let $L$ be the language $$L = \{ w \in \Sigma^* \mid |w|_0 \gt |...

How to show that the language containing the words whose length is a power of $2$, $L=\{w\mid|w|=2^i\}$, isn't regular using the pumping lemma? The pumping lemma says that Let be M a regular language....

I need to prove that the following language is not regular $\{c^mb^na^n \mid n>0,m\geq0\}$ But I am not sure how to do that for this particular one. I vaguely understand pumping lemma, but ...

L ={ $a^{m^n}$ | $m$>$n$ } I am bit confuse whether to consider this language as L = $(a^{m})^{n}$ OR L = $a^{\left(m^n\right)}$. If it is considered as L = $(a^m)^{n}$ then want to check it ...

Using pumping lemma, how can I prove that $L=\{a^n b^m c^k \mid n = m \vee m\neq k\}$ is not regular?. If I choose $w= a^m b^m c^m$ and pump up with $i=2$, if have $a^m=1 b^m c^m$ but the string is ...

I'm struggling to understand this question using pumping lemma to prove a language is not regular. Any help would be appreciated. Prove using the Pumping Lemma that the following language is not ...

I am working on a pumping lemma question and trying to prove that the following is not regular, but I can't finish the proof, if someone can help me it will be great. So I am given this language: $L ...

I'm trying to study for the summer ahead of class I saw this question, please how do I go about it? Find NFA/DFA for the language $L = \{0^n1^n : n \in N\}$

The question I'm working from is: Prove whether or not a finite automation exists that recognises the following language: B = {ww | w ∈ {a,b,c,...,z)*} EDIT So I believe this is a non-regular ...

Possible Duplicate: How to prove that a language is not regular? Why $L_a$ and $L_b$ are not reguluar? $L_a = \{ e^i f^{n-i} g^j h^{n-j} : n \in N, 1 \leq i, j \leq n \}$. $L_b= \{nm^{i_1} ...

Consider the language defined by the following grammar: $$ \begin{align*} &S \rightarrow E \\ &S \rightarrow \epsilon \\ &E \rightarrow E+E \\ &E \rightarrow E-E \\ &E \rightarrow \...

I'm trying to prove that the set of even-length strings with the two middle symbols being equal cannot be accepted by finite automata. I can explain why it cannot be accepted intuitively, but I'm ...

Consider the non-regular language $L_1$ = {$a^n$b$a^n$: $n \geq 0$} and its super-set language L = Language of strings with equal number of trailing and leading a's, or in other words, $$L = \{a^...

I was searching for a difference on both ways of proving that a language is not regular but I didn't came up with much. Let us take the following as an example: $$ L = \{ a^n b^n \mid n \ge 0\} $$ ...

$D → T ∨ D | T$ $T → C ∧ T | C$ $C → ¬C | name | ( D )$ $name → a | b | c | d$ I am not looking for the complete answer, but more the methodology of working this out. How would I go about proving ...

What are the common ways to check if a given language is regular, context free, or context sensitive? Any surveys or notes would also be helpful. There's no need to describe your suggestions. eg. it ...

i had troubles proving this is not regular using the pumping lemma {$a^ib^jc^k : j = i \lor j = k$}. Not sure how to approach this anymore, and help would be appreciated

I'm trying to understand the approach to constructing an grammar which accepts the language ${a^ib^j \mid i>0\ and \hspace{2.5mm}i\leq j \leq(2*i)}$ } Thanks.

I have the languages $L_1$ and $L_2$ such that $L_1 = \{a^nba^n :n \in N\}$ and $L_2 =\{a,b\}^*\setminus L_1$. I want to prove that $L_2$ is not a regular language. I know that to prove that $L_2$ is ...

I am unsure of how to prove this language is non-regular. I do not even know where to start to develop a string that would prove the language is non-regular by contradiction. Any help would be ...

I'm trying to show that $L_6=\{c^n a^m b^p : n+m=p,p \geq 6\}$ is not regular. I need a little help, I was practicing the pumping lemma, and I encountered this language, I saw these conditions and got ...

Show that the following languages are not regular: $(1)\ L=\left\{a^nb^mc^k\mid n>k \land n,m,k>0\right\}$ $(2)\ L=\left\{a^nb^mc^k\mid m>k \land n,m,k>0\right\}$ I've difficulties ...

I'm trying to show that the language in the title is not regular but I don't know how to chose a decomposition $x = abc$ to express the word in the language because the $w \in \{a,b,c\}^*$ is kinda ...