Cyclic notation for residue classes mod $n$

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I am reading an example from Dummit and Foote's Abstract Algebra, 3rd edition.



I am wondering why the authors do not use the bar notation for the element of residue classes.
For example, why do they write $mathbbZ/2mathbbZ=langle~1~rangle$ instead of $mathbbZ/2mathbbZ=langle~bar1~rangle$?



The reason why I am confused is that they once use the bar notation when they introduce groups $mathbbZ/nmathbbZ$ and suddenly switche to this notation. Is it a common practice not to use the bar when denoting an element of $mathbbZ/nmathbbZ$, or is there any other reason for why they do not use the bar notation here?



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  • 2




    It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
    – Berci
    Aug 17 at 1:22






  • 2




    Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
    – Randall
    Aug 17 at 1:26














up vote
1
down vote

favorite












I am reading an example from Dummit and Foote's Abstract Algebra, 3rd edition.



I am wondering why the authors do not use the bar notation for the element of residue classes.
For example, why do they write $mathbbZ/2mathbbZ=langle~1~rangle$ instead of $mathbbZ/2mathbbZ=langle~bar1~rangle$?



The reason why I am confused is that they once use the bar notation when they introduce groups $mathbbZ/nmathbbZ$ and suddenly switche to this notation. Is it a common practice not to use the bar when denoting an element of $mathbbZ/nmathbbZ$, or is there any other reason for why they do not use the bar notation here?



enter image description here







share|cite|improve this question
















  • 2




    It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
    – Berci
    Aug 17 at 1:22






  • 2




    Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
    – Randall
    Aug 17 at 1:26












up vote
1
down vote

favorite









up vote
1
down vote

favorite











I am reading an example from Dummit and Foote's Abstract Algebra, 3rd edition.



I am wondering why the authors do not use the bar notation for the element of residue classes.
For example, why do they write $mathbbZ/2mathbbZ=langle~1~rangle$ instead of $mathbbZ/2mathbbZ=langle~bar1~rangle$?



The reason why I am confused is that they once use the bar notation when they introduce groups $mathbbZ/nmathbbZ$ and suddenly switche to this notation. Is it a common practice not to use the bar when denoting an element of $mathbbZ/nmathbbZ$, or is there any other reason for why they do not use the bar notation here?



enter image description here







share|cite|improve this question












I am reading an example from Dummit and Foote's Abstract Algebra, 3rd edition.



I am wondering why the authors do not use the bar notation for the element of residue classes.
For example, why do they write $mathbbZ/2mathbbZ=langle~1~rangle$ instead of $mathbbZ/2mathbbZ=langle~bar1~rangle$?



The reason why I am confused is that they once use the bar notation when they introduce groups $mathbbZ/nmathbbZ$ and suddenly switche to this notation. Is it a common practice not to use the bar when denoting an element of $mathbbZ/nmathbbZ$, or is there any other reason for why they do not use the bar notation here?



enter image description here









share|cite|improve this question











share|cite|improve this question




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asked Aug 17 at 1:10









kmiyazaki

33711




33711







  • 2




    It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
    – Berci
    Aug 17 at 1:22






  • 2




    Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
    – Randall
    Aug 17 at 1:26












  • 2




    It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
    – Berci
    Aug 17 at 1:22






  • 2




    Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
    – Randall
    Aug 17 at 1:26







2




2




It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
– Berci
Aug 17 at 1:22




It's very common practice. Also, it is aligned with defining $n:=overbrace1+dots+1^n$ where $1$ is the multiplicative identity.
– Berci
Aug 17 at 1:22




2




2




Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
– Randall
Aug 17 at 1:26




Try typsetting a paper or 200-page thesis with bars everywhere. You'll come around.
– Randall
Aug 17 at 1:26










1 Answer
1






active

oldest

votes

















up vote
4
down vote



accepted










As you can see the author is now discussing the subgroups of $G=Z_n$, not $BbbZ/nBbbZ$, that's why different notation is used.

In the book, the author denotes $Z_n=0,1,dots,n-1$ and $BbbZ/nBbbZ=bar0,bar1,dots,overlinen-1$






share|cite|improve this answer






















  • I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
    – Derek Holt
    Aug 17 at 7:39










  • @DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
    – Alan Wang
    Aug 17 at 9:26










  • @DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
    – Henning Makholm
    Aug 17 at 9:27










  • @HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
    – Derek Holt
    Aug 17 at 10:27










  • @AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
    – kmiyazaki
    Aug 17 at 19:32











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
4
down vote



accepted










As you can see the author is now discussing the subgroups of $G=Z_n$, not $BbbZ/nBbbZ$, that's why different notation is used.

In the book, the author denotes $Z_n=0,1,dots,n-1$ and $BbbZ/nBbbZ=bar0,bar1,dots,overlinen-1$






share|cite|improve this answer






















  • I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
    – Derek Holt
    Aug 17 at 7:39










  • @DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
    – Alan Wang
    Aug 17 at 9:26










  • @DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
    – Henning Makholm
    Aug 17 at 9:27










  • @HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
    – Derek Holt
    Aug 17 at 10:27










  • @AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
    – kmiyazaki
    Aug 17 at 19:32















up vote
4
down vote



accepted










As you can see the author is now discussing the subgroups of $G=Z_n$, not $BbbZ/nBbbZ$, that's why different notation is used.

In the book, the author denotes $Z_n=0,1,dots,n-1$ and $BbbZ/nBbbZ=bar0,bar1,dots,overlinen-1$






share|cite|improve this answer






















  • I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
    – Derek Holt
    Aug 17 at 7:39










  • @DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
    – Alan Wang
    Aug 17 at 9:26










  • @DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
    – Henning Makholm
    Aug 17 at 9:27










  • @HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
    – Derek Holt
    Aug 17 at 10:27










  • @AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
    – kmiyazaki
    Aug 17 at 19:32













up vote
4
down vote



accepted







up vote
4
down vote



accepted






As you can see the author is now discussing the subgroups of $G=Z_n$, not $BbbZ/nBbbZ$, that's why different notation is used.

In the book, the author denotes $Z_n=0,1,dots,n-1$ and $BbbZ/nBbbZ=bar0,bar1,dots,overlinen-1$






share|cite|improve this answer














As you can see the author is now discussing the subgroups of $G=Z_n$, not $BbbZ/nBbbZ$, that's why different notation is used.

In the book, the author denotes $Z_n=0,1,dots,n-1$ and $BbbZ/nBbbZ=bar0,bar1,dots,overlinen-1$







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Aug 17 at 9:23

























answered Aug 17 at 1:47









Alan Wang

4,486932




4,486932











  • I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
    – Derek Holt
    Aug 17 at 7:39










  • @DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
    – Alan Wang
    Aug 17 at 9:26










  • @DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
    – Henning Makholm
    Aug 17 at 9:27










  • @HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
    – Derek Holt
    Aug 17 at 10:27










  • @AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
    – kmiyazaki
    Aug 17 at 19:32

















  • I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
    – Derek Holt
    Aug 17 at 7:39










  • @DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
    – Alan Wang
    Aug 17 at 9:26










  • @DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
    – Henning Makholm
    Aug 17 at 9:27










  • @HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
    – Derek Holt
    Aug 17 at 10:27










  • @AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
    – kmiyazaki
    Aug 17 at 19:32
















I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
– Derek Holt
Aug 17 at 7:39




I try to avoid using $mathbb Z_n$ because it causes so much confusion, but if I do use it then I define it to be equal to $mathbb Z/nmathbb Z$. Denoting $bar1$ by $1$ is just a convenient abuse of notation.
– Derek Holt
Aug 17 at 7:39












@DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
– Alan Wang
Aug 17 at 9:26




@DerekHolt Ya actually both notation are the same in the sense that the two groups stated are isomorphic, and denoting $bar1$ by $1$ is simpler.
– Alan Wang
Aug 17 at 9:26












@DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
– Henning Makholm
Aug 17 at 9:27




@DerekHolt: Do you think calling the multiplicative identity in a (unitary) ring $1$ is always an "abuse of notation", or is that only when the ring happens to be a quotient of $mathbb Z$?
– Henning Makholm
Aug 17 at 9:27












@HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
– Derek Holt
Aug 17 at 10:27




@HenningMakholm I think perhaps that abuse of notation was not exactly what I meant. I meant a simplification of notation to be used when there is no danger of confusion. So I would denote the multiplicative identity in a ring $R$ by $1_R$, but say we will usually just write $1$. Unfortunately many students do succeed in getting confused!
– Derek Holt
Aug 17 at 10:27












@AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
– kmiyazaki
Aug 17 at 19:32





@AlanWang I thought that even if it was a convention to denote the elements of $mathbbZ/nmathbbZ$ simply by $0, 1, ldots, n-1$, the authors would say so before using the convention. And it was actually the case. They mention it on page 10. Thank you.
– kmiyazaki
Aug 17 at 19:32













 

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