## Prove that the class of regular languages is closed under the Kleene + operation. That is, show that if L is regular, then so is \$L^{+}\$

This is my attempt at a proof:

Let $$E$$ be a $$REGEX$$ accepting $$L$$. We claim the $$REGEX$$ $$E^{‘} = E^{+}$$ accepts L. i.e. $$L(E^{+}) = (L(E))^{+}$$
$$L^{+}$$ is regular since there is a $$REGEX$$ $$E^{+}$$ accepting $$L$$

I am very unsure if my proof makes sense or is correct. Can someone please advise?

## formal languages – Create an Finite Deterministic Automata for a regular expression

I want to create a finite state machine that accepts the following language:

$$L={win{a,b}^* | w text{ contains abb but not on the first position}}$$

So I began by writing a regular expression from this and this is what I came up with:

$$(a+b)(a+b)^*abb(a+b)^*$$

And for the finite state machine I tried to do this:

But it doesn’t work since I can go from qo->(a)q1->(b)->(b)q1 and have $$abb$$ at the begining. How should I approach this? How should I approach to create a finite state machine when for example I have the regular expression? How should I develop an intuition without using algorithms such as FollowPos?

## How to stop multi-word links being placed together on a new line, instead splitting them up like regular text? [closed]

On one of my posts I have the following text.

Any readers interested in the different ways to interpret utils are encouraged to read about the difference between Ordinal and Cardinal Utility.

If WordPress can’t put all of the text "Ordinal and Cardinal Utility" on the same line as "between" it puts it all on a completely new line, which can look really clunky, especially on mobile. Because it’s a hyperlink it’s prioritising keeping it as one item whereas I’m happy for the words to be split over multiple lines, just as it would if it wasn’t a hyperlink. I know this is a basic problem but for some reason I haven’t found any solutions online. Is there an easy way to fix this?

## ubuntu 14.04 – Auditd – track commands (regular and sudo) of a given UID

I have some `auditd` rules like:

``````-a always,exit -F arch=b32 -S execve -F euid=1002 -k mytag
-a always,exit -F arch=b64 -S execve -F euid=1002 -k mytag

-a always,exit -F arch=b32 -S execve -F euid=1003 -k mytag
-a always,exit -F arch=b64 -S execve -F euid=1003 -k mytag
``````

Which is working fine, but I want to also track the `sudo` commands run
by these users, so I added

``````-a always,exit -F arch=b32 -S execve -F euid=0 -k mytag
-a always,exit -F arch=b64 -S execve -F euid=0 -k mytag
``````

But the `sudo` commands do not seem to be tagged with the key. Is there anything
wrong with specifying both these set of commands. Does the order of these rules
matter?

## How to check if a language is not regular?

I have the given regular language and i am suppose to check if it is regular and if it is, to provide a regular expression

However, if the language is not regular i have to prove using the “Pumping Lemma” that it is not regular

• it is regular if, it can be represented by a finite state automata (FSA)

• or, if it can be represented by a regular expression

``````L = { a^2 b^n c^m , where n,m >= 0 }  Alphabet is {a,b,c}
``````

My thoughts:

At first glance, i thought this language is regular because it can be represented by a regular expression. The regular expression that i would propose would be `a^2 b^* c^*`, is this correct?

## formulas – Google Sheets Use Regular Expressions to Add Text to Cells

I have a bunch of words in a sheet in one column, e.g.:

• Study Guide 101
• Meditation for Beginners Cheatsheet
• Lose Weight Fast

What I want to do is add a word to the end of these in the cell using Find & Replace (not a formula), through regular expressions, without using a formula or anything in another cell. The word to add would be `- EBOOK`

The same way can we can text to the front of the strings in cells, in this case `DD-EB-` (just an example).

I’m not sure whether this is entirely possible, but I got the idea from this youtube video: