Help understanding <g> for Z/mZ

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In summary, the conversation discussed the concept of <g> as the set of all integer powers of g and examples were done in \mathbb{Z} / 7\mathbb{Z}. The speaker was having trouble understanding \bmod{n} as an equivalence class, specifically in the context of showing that \mathbb{Z} / 7\mathbb{Z} is cyclic. They were also struggling with computations in \mathbb{Z} / n\mathbb{Z} and the definition of <g> when the group operation is addition. The speaker later realized their mistake and the issue was resolved.
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Convergence
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Hello. So today in class, we talked a bit about [itex]<g>[/itex] as the set of all integer powers of [itex]g[/itex]. Made enough sense. Then we did some examples in [itex]\mathbb{Z} / 7\mathbb{Z}[/itex], and I got a bit lost. I think this is more due to the fact that perhaps I don't quite grasp [itex]\bmod{n}[/itex] as an equivalence class. So I know that the elements of [itex]\mathbb{Z} / 7\mathbb{Z}[/itex] are [itex]\{ [0], [1], [2], [3], [4], [5], [6] \}[/itex], but we were looking for [itex]<g>[/itex] where [itex]g = [5][/itex]. The idea was we were showing that [itex]\mathbb{Z} / 7\mathbb{Z}[/itex] is cyclic. Since we were "brute-forcing" it so to speak, we wrote down elements in a certain order, which I have written down as [itex]\{ [0], [5], [3], [1], [6], [4], [2] \}[/itex] and then it cycled back to [itex][0][/itex].
So I suppose I'm having trouble doing computations in [itex]\mathbb{Z} / 7\mathbb{Z}[/itex], or [itex]\mathbb{Z} / n\mathbb{Z}[/itex] in general. I mean, I know that if [itex]a \equiv b \bmod{n}[/itex] then [itex]n \mid a-b[/itex], but in this case I'm not sure where to take it. Is it:
[itex]5^0 = 1 \equiv[/itex] something [itex]\bmod{7}[/itex], then [itex]5^1 = 5 \equiv[/itex] something [itex]\bmod{7}[/itex] etc?
Sorry if my question(s) is a bit hard to read; perhaps I didn't explain it as best I could. But any help would be appreciated.
 
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  • #2
NEVER MIND!

Sorry, it's late, but I totally forgot the definition of $<g>$ when the group operation is addition. I computed it for that, and my results matched. I guess my problem is not with the computation, but rather when I need to take a break and go to sleep. I'm not sure I can close/delete this thread, so I'm posting this just in case.
 

1. What is Z/mZ?

Z/mZ refers to the set of integers modulo m, where m is a positive integer. This set includes all integers from 0 to m-1, and follows certain rules for addition and multiplication.

2. How is Z/mZ different from regular integers?

In regular integers, there is no limit to the size of the numbers. However, in Z/mZ, all numbers are limited to the range of 0 to m-1. Additionally, in Z/mZ, there are specific rules for addition and multiplication, such as the fact that (m-1) + 1 = 0.

3. How can Z/mZ be applied in real life?

Z/mZ has various applications in cryptography, coding theory, and number theory. It is also used in computer science and engineering for error-correction codes and data compression algorithms.

4. What are the benefits of using Z/mZ in mathematical concepts?

Using Z/mZ allows for easier calculations and simplification of complex mathematical concepts. It also helps in finding patterns and solving problems that involve large numbers. Additionally, Z/mZ helps in creating efficient algorithms for computer programs.

5. Are there any resources available for further understanding of Z/mZ?

Yes, there are several books, online resources, and courses available for learning about Z/mZ and its applications. Some recommended resources include "A Concrete Introduction to Higher Algebra" by Lindsay Childs and "Introduction to the Theory of Numbers" by Ivan Niven and Herbert Zuckerman.

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