问题


There is a single choice question about abstract algebra. Answer the question by replying A, B, C or D.
Question: Find all cosets of the subgroup 4Z of 2Z.
A. 4Z
B. 4Z, 2 + 4Z
C. 2Z
D. Z
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

B. 4Z, 2 + 4Z

Explanation:

The subgroup 4Z of 2Z consists of all multiples of 4, i.e., {..., -8, -4, 0, 4, 8, ...}.

To find the cosets of 4Z in 2Z, we need to find the sets of elements in 2Z that are not in 4Z but can be obtained by adding a fixed element of 2Z to 4Z.

Since 2Z consists of all even integers, we can write 2Z = {..., -4, -2, 0, 2, 4, ...}.

Now, let's consider the element 2, which is in 2Z but not in 4Z. We can add 2 to each element of 4Z to get a new set of elements:

2 + 4Z = {..., -6, -2, 2, 6, 10, ...}

This set is not equal to 4Z, so it is a new coset.

We can continue this process with other elements of 2Z, but we will find that all other elements either give us the same coset as 2 + 4Z or give us 4Z itself.

Therefore, the cosets of 4Z in 2Z are 4Z and 2 + 4Z.
B
deepseekr1

The question asks for all cosets of the subgroup \(4\mathbb{Z}\) in \(2\mathbb{Z}\). The group \(2\mathbb{Z}\) consists of all even integers, and \(4\mathbb{Z}\) (a subgroup of \(2\mathbb{Z}\)) contains multiples of 4. To find the cosets, note that \(2\mathbb{Z}/4\mathbb{Z}\) has an index of 2 since \(2\mathbb{Z}\) is "twice as large" as \(4\mathbb{Z\). The cosets are formed by adding representatives from \(2\mathbb{Z}\) to \(4\mathbb{Z}\). The distinct cosets are \(0 + 4\mathbb{Z} = 4\mathbb{Z}\) (the subgroup itself) and \(2 + 4\mathbb{Z}\), which covers all even integers congruent to 2 modulo 4. These two cosets exhaust \(2\mathbb{Z}\).

**Answer:** B. 4Z, 2 + 4Z
B
gpto1 B B
GPT-4o B. 4Z, 2 + 4Z B
llama3.1-70B-Instruct

B
B
llama3.1-405B-Instruct

The correct answer is B. 4Z, 2 + 4Z.

Explanation:

The subgroup 4Z of 2Z consists of all multiples of 4, i.e., 4Z = {..., -8, -4, 0, 4, 8, ...}.

To find the cosets of 4Z in 2Z, we need to find the sets of elements in 2Z that are not in 4Z but can be obtained by adding an element of 4Z to an element of 2Z.

One such coset is 2 + 4Z, which consists of all elements of the form 2 + 4k, where k is an integer. This coset includes elements such as 2, 6, 10, ... .

There are no other cosets of 4Z in 2Z, since any element of 2Z that is not in 4Z can be written as 2 + 4k for some integer k.

Therefore, the cosets of 4Z in 2Z are 4Z and 2 + 4Z.
B
DeepSeek-Coder-V2 B. 4Z, 2 + 4Z B
Qwen2-72B-Instruct B. 4Z, 2 + 4Z B
baichuan4 B. 4Z, 2 + 4Z B
doubao B

The cosets of 4Z in 2Z are 4Z and 2 + 4Z.
B
minimax B. 4Z, 2 + 4Z

Explanation: The subgroup 4Z (all multiples of 4) is a subgroup of 2Z (all multiples of 2). The cosets of 4Z in 2Z are formed by adding an element from 2Z that is not in 4Z to each element of 4Z. Since 2Z consists of all even integers and 4Z consists of all integers that are multiples of 4, the cosets are:

1. The subgroup itself, which is 4Z.
2. The set of all integers that are not multiples of 4 but are multiples of 2, which can be represented as 2 + 4Z (all even numbers that are not divisible by 4).

These are the only two cosets because any other coset would either be a subset of 4Z or would not be a coset at all.
B
kimi B. 4Z, 2 + 4Z B
wenxinyiyan B

Explanation:
The subgroup $4\mathbb{Z}$ of $2\mathbb{Z}$ consists of all multiples of 4, i.e., {...,-8,-4,0,4,8,...}.

To find all cosets of $4\mathbb{Z}$ in $2\mathbb{Z}$, we consider elements of $2\mathbb{Z}$ (which are all multiples of 2) and add them to $4\mathbb{Z}$.

1. Taking 0 (which is in $2\mathbb{Z}$) and adding it to $4\mathbb{Z}$ gives us $0 + 4\mathbb{Z} = 4\mathbb{Z}$.
2. Taking 2 (which is also in $2\mathbb{Z}$) and adding it to $4\mathbb{Z}$ gives us $2 + 4\mathbb{Z}$. This coset consists of elements {...,-6,-2,2,6,...}.

Note that any other even number added to $4\mathbb{Z}$ will either give $4\mathbb{Z}$ or $2 + 4\mathbb{Z}$. For example, 4 + $4\mathbb{Z}$ = $4\mathbb{Z}$ and 6 + $4\mathbb{Z}$ = 2 + $4\mathbb{Z}$.

Therefore, the cosets of $4\mathbb{Z}$ in $2\mathbb{Z}$ are $4\mathbb{Z}$ and $2 + 4\mathbb{Z}$.
B
zhipu To find all cosets of the subgroup \(4\mathbb{Z}\) of \(2\mathbb{Z}\), we need to understand the structure of these groups.

- \(2\mathbb{Z}\) is the set of all even integers: \(\{ \ldots, -4, -2, 0, 2, 4, \ldots \}\).
- \(4\mathbb{Z}\) is the set of all integers divisible by 4: \(\{ \ldots, -8, -4, 0, 4, 8, \ldots \}\).

A coset of \(4\mathbb{Z}\) in \(2\mathbb{Z}\) is of the form \(a + 4\mathbb{Z}\) for some \(a \in 2\mathbb{Z}\).

Let's analyze possible values of \(a\):
- If \(a \in 4\mathbb{Z}\), then \(a + 4\mathbb{Z} = 4\mathbb{Z}\).
- If \(a \in 2\mathbb{Z}\) but \(a \notin 4\mathbb{Z}\), the smallest such \(a\) is 2 (since 2 is even but not divisible by 4).

Thus, the cosets can be:
- \(4\mathbb{Z}\)
- \(2 + 4\mathbb{Z}\)

These are the only distinct cosets because any other even integer \(a\) not in \(4\mathbb{Z}\) will fall into the coset \(2 + 4\mathbb{Z}\) (since adding or subtracting multiples of 4 will bring it back to either \(4\mathbb{Z}\) or \(2 + 4\mathbb{Z}\)).

So, the cosets of \(4\mathbb{Z}\) in \(2\mathbb{Z}\) are \(4\mathbb{Z}\) and \(2 + 4\mathbb{Z}\).

The correct answer is:
B. 4Z, 2 + 4Z
B
gpto1 B B
deepseekv3 The correct answer is **B**.

### Explanation:
1. The subgroup \(4\mathbb{Z}\) of \(2\mathbb{Z}\) consists of all multiples of 4: \(4\mathbb{Z} = \{..., -8, -4, 0, 4, 8, ...\}\).
2. The cosets of \(4\mathbb{Z}\) in \(2\mathbb{Z}\) are of the form \(a + 4\mathbb{Z}\), where \(a \in 2\mathbb{Z}\).
3. Since \(2\mathbb{Z} = \{..., -4, -2, 0, 2, 4, ...\}\), the distinct cosets are:
- \(0 + 4\mathbb{Z} = 4\mathbb{Z}\),
- \(2 + 4\mathbb{Z} = \{..., -6, -2, 2, 6, ...\}\).
4. These are the only distinct cosets.

Thus, the cosets are \(4\mathbb{Z}\) and \(2 + 4\mathbb{Z}\). The correct answer is **B**.
B