Find a group G that has subgroups isomorphic to $mathbbZ_n$ for all natural numbers n $geq$ 2
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I was thinking of using the theorem: " If G is finite of order n, then $G cong mathbbZ_n$ " But cannot find an appropriate group.
Any help is appreciated, thanks.
EDIT: The correct version of the theorem is "If G is cyclic AND finite of order n, then $G cong mathbbZ_n$ "
abstract-algebra group-theory finite-groups
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up vote
1
down vote
favorite
I was thinking of using the theorem: " If G is finite of order n, then $G cong mathbbZ_n$ " But cannot find an appropriate group.
Any help is appreciated, thanks.
EDIT: The correct version of the theorem is "If G is cyclic AND finite of order n, then $G cong mathbbZ_n$ "
abstract-algebra group-theory finite-groups
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I was thinking of using the theorem: " If G is finite of order n, then $G cong mathbbZ_n$ " But cannot find an appropriate group.
Any help is appreciated, thanks.
EDIT: The correct version of the theorem is "If G is cyclic AND finite of order n, then $G cong mathbbZ_n$ "
abstract-algebra group-theory finite-groups
I was thinking of using the theorem: " If G is finite of order n, then $G cong mathbbZ_n$ " But cannot find an appropriate group.
Any help is appreciated, thanks.
EDIT: The correct version of the theorem is "If G is cyclic AND finite of order n, then $G cong mathbbZ_n$ "
abstract-algebra group-theory finite-groups
edited Jul 22 at 18:23
asked Jul 22 at 18:04
Wallace
625
625
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4 Answers
4
active
oldest
votes
up vote
6
down vote
accepted
An easy example is the multiplicative group of the complex numbers. For each $n$ it has exactly one cyclic subgroup of order $n$, consisting of the solutions of $z^n-1=0$.
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
add a comment |Â
up vote
3
down vote
It is not true that every finite group of order $n$ is isomorphic to $Bbb Z_n$.
However, you can take $G = displaystyle prod_n ge 2 Bbb Z_n$, where $prod$ means direct product.
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
add a comment |Â
up vote
2
down vote
Let $mathbb S = mathbb R/1$, the set of all real numbers modulo $1$, i.e. the set of all sets of the form $[x] = x + n $. Addition on $mathbb S$ is defined by $[x]+[y] =[x+y]$. Then $mathbb S$ is an abelian group with respect to addition. For any positive integer, $n$, the order of the group generated by $[frac 1n]$ is $n$.
add a comment |Â
up vote
1
down vote
It's a bit silly, but you can use Cayley's theorem that states that every finite group is embedded in some symmetric group $S_n$, and then
$$
G = prod_n in mathbb N S_n
$$
will be a group that contains any finite group as a subgroup. This also is true for the symmetric group of the natural numbers $S(mathbb N)$, since it contains all $S_n$ as subgroups.
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
add a comment |Â
4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
6
down vote
accepted
An easy example is the multiplicative group of the complex numbers. For each $n$ it has exactly one cyclic subgroup of order $n$, consisting of the solutions of $z^n-1=0$.
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
add a comment |Â
up vote
6
down vote
accepted
An easy example is the multiplicative group of the complex numbers. For each $n$ it has exactly one cyclic subgroup of order $n$, consisting of the solutions of $z^n-1=0$.
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
add a comment |Â
up vote
6
down vote
accepted
up vote
6
down vote
accepted
An easy example is the multiplicative group of the complex numbers. For each $n$ it has exactly one cyclic subgroup of order $n$, consisting of the solutions of $z^n-1=0$.
An easy example is the multiplicative group of the complex numbers. For each $n$ it has exactly one cyclic subgroup of order $n$, consisting of the solutions of $z^n-1=0$.
answered Jul 22 at 18:08
Lord Shark the Unknown
85.2k950111
85.2k950111
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
add a comment |Â
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
Could you elaborate on why for each n it has exactly one cyclic subgroup of order n?
– Wallace
Jul 22 at 18:17
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
I think I'm starting to see why this is true, my knowledge on complex analysis is a bit groggy as of now.
– Wallace
Jul 22 at 18:26
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
All the solutions of $z^n=1$ are powers of $exp(2pi i/n)$. @Wallace
– Lord Shark the Unknown
Jul 22 at 18:27
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
Perfect! Thank you!
– Wallace
Jul 22 at 18:28
add a comment |Â
up vote
3
down vote
It is not true that every finite group of order $n$ is isomorphic to $Bbb Z_n$.
However, you can take $G = displaystyle prod_n ge 2 Bbb Z_n$, where $prod$ means direct product.
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
add a comment |Â
up vote
3
down vote
It is not true that every finite group of order $n$ is isomorphic to $Bbb Z_n$.
However, you can take $G = displaystyle prod_n ge 2 Bbb Z_n$, where $prod$ means direct product.
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
add a comment |Â
up vote
3
down vote
up vote
3
down vote
It is not true that every finite group of order $n$ is isomorphic to $Bbb Z_n$.
However, you can take $G = displaystyle prod_n ge 2 Bbb Z_n$, where $prod$ means direct product.
It is not true that every finite group of order $n$ is isomorphic to $Bbb Z_n$.
However, you can take $G = displaystyle prod_n ge 2 Bbb Z_n$, where $prod$ means direct product.
answered Jul 22 at 18:08


Kenny Lau
18.7k2157
18.7k2157
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
add a comment |Â
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
I'm actually interested about your first statement. Could you provide me a counter example of a group with order n that is not isomorphic to $mathbbZ_n$?
– Wallace
Jul 22 at 18:18
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
en.wikipedia.org/wiki/List_of_small_groups
– Kenny Lau
Jul 22 at 18:19
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@Wallace You know that there are non-abelian groups. They give enough counterexamples...
– Dietrich Burde
Jul 22 at 18:20
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
@KennyLau, thank you for providing me with this. It appears I have misread the theorem. It requires G to be cyclic! Thank you for this clarification. I will edit my original post
– Wallace
Jul 22 at 18:22
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
The order of the group $mathbb Z_2 times mathbb Z_2$ is not isomorphic to $mathbb Z_4$
– steven gregory
Jul 22 at 23:38
add a comment |Â
up vote
2
down vote
Let $mathbb S = mathbb R/1$, the set of all real numbers modulo $1$, i.e. the set of all sets of the form $[x] = x + n $. Addition on $mathbb S$ is defined by $[x]+[y] =[x+y]$. Then $mathbb S$ is an abelian group with respect to addition. For any positive integer, $n$, the order of the group generated by $[frac 1n]$ is $n$.
add a comment |Â
up vote
2
down vote
Let $mathbb S = mathbb R/1$, the set of all real numbers modulo $1$, i.e. the set of all sets of the form $[x] = x + n $. Addition on $mathbb S$ is defined by $[x]+[y] =[x+y]$. Then $mathbb S$ is an abelian group with respect to addition. For any positive integer, $n$, the order of the group generated by $[frac 1n]$ is $n$.
add a comment |Â
up vote
2
down vote
up vote
2
down vote
Let $mathbb S = mathbb R/1$, the set of all real numbers modulo $1$, i.e. the set of all sets of the form $[x] = x + n $. Addition on $mathbb S$ is defined by $[x]+[y] =[x+y]$. Then $mathbb S$ is an abelian group with respect to addition. For any positive integer, $n$, the order of the group generated by $[frac 1n]$ is $n$.
Let $mathbb S = mathbb R/1$, the set of all real numbers modulo $1$, i.e. the set of all sets of the form $[x] = x + n $. Addition on $mathbb S$ is defined by $[x]+[y] =[x+y]$. Then $mathbb S$ is an abelian group with respect to addition. For any positive integer, $n$, the order of the group generated by $[frac 1n]$ is $n$.
answered Jul 22 at 18:23
steven gregory
16.4k22055
16.4k22055
add a comment |Â
add a comment |Â
up vote
1
down vote
It's a bit silly, but you can use Cayley's theorem that states that every finite group is embedded in some symmetric group $S_n$, and then
$$
G = prod_n in mathbb N S_n
$$
will be a group that contains any finite group as a subgroup. This also is true for the symmetric group of the natural numbers $S(mathbb N)$, since it contains all $S_n$ as subgroups.
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
add a comment |Â
up vote
1
down vote
It's a bit silly, but you can use Cayley's theorem that states that every finite group is embedded in some symmetric group $S_n$, and then
$$
G = prod_n in mathbb N S_n
$$
will be a group that contains any finite group as a subgroup. This also is true for the symmetric group of the natural numbers $S(mathbb N)$, since it contains all $S_n$ as subgroups.
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
add a comment |Â
up vote
1
down vote
up vote
1
down vote
It's a bit silly, but you can use Cayley's theorem that states that every finite group is embedded in some symmetric group $S_n$, and then
$$
G = prod_n in mathbb N S_n
$$
will be a group that contains any finite group as a subgroup. This also is true for the symmetric group of the natural numbers $S(mathbb N)$, since it contains all $S_n$ as subgroups.
It's a bit silly, but you can use Cayley's theorem that states that every finite group is embedded in some symmetric group $S_n$, and then
$$
G = prod_n in mathbb N S_n
$$
will be a group that contains any finite group as a subgroup. This also is true for the symmetric group of the natural numbers $S(mathbb N)$, since it contains all $S_n$ as subgroups.
answered Jul 22 at 18:43
AlgebraicsAnonymous
69111
69111
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
add a comment |Â
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
1
1
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
I think you can take the subgroup of $G$ consisting of elements with finite support.
– Kenny Lau
Jul 23 at 1:53
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
Yes, then we'd even be countable!
– AlgebraicsAnonymous
Jul 28 at 7:06
add a comment |Â
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