# Questions tagged [regular-languages]

Questions about properties of the class of regular languages and individual languages.

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### How to do Big 'O' notations [duplicate]

How can I solve $\mathcal{O}$-notations without using Java or any other programming language? I only want to use pen and paper.
40 views

9k views

### Regular expression for all strings with at least two 0s over alphabet {0,1}

My answer : (0+1)* 0 (0+1)* 0 (0+1)* Why is this incorrect? Can somebody explain to me what the correct answer is and why?
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### Prove A² is regular [duplicate]

Suppose that $A$ is a regular language. How can I show that $A^2 = A \cdot A$ is a regular language? Is there a construction?
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### Regular and context free languages

I need to determine if the following languages are regular / context free and to explain. Please help me with that. L_1 = \{ a^{i_{1}}b a^{i_{2}}b a^{i_{3}}b a^{i_{4}}b a^{i_{5}}b a^{i_{6}}b a^{i_{...
3k views

### Are all irregular languages infinite? [duplicate]

How can I prove whether irregular languages are infinite? I thought about proving it by the definition of regular language but got stuck.
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### The language of all base-10 integers that are multiples of 9 [closed]

If I want to represent all the base 10 integers that are multiples of 9 as a language how do I do so? Alphabets are finite sets.
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### The set of all words containing more 1's than 2s [closed]

I'm currently working through some regular expression questions and I've got a solution for one of the problems that I'm not certain is correct. The question has this preface. We only consider ...
96 views

### Show whether the language with almost as many 0 as 1 in every prefix is regular [closed]

This is the exercise: Let A be a language defined over the alphabet Σ = {0, 1} composed by the strings with the property that in every prefix, the number of 0s and the number of 1s differ by at ...
This is our alphabet: $\{0,1,2\}$ And lets say I have two regular expressions: Regular expression 1. $(1|22|0)^* (2|0)^*$ Regular expression 2. $(0|1)^* (1|20|1)^*$ How can I give three words each ...
I was wondering if there was a method that can be used to generate a Regular Expression for a language. Take the Language $L$ as an example where: \$L= \{w \in \{0, 1\}^{\ast} \mid \text{length of } w ...