问题


There is a single choice question about abstract algebra. Answer the question by replying A, B, C or D.
Question: Statement 1 | A ring homomorphism is one to one if and only if the kernel is {0}. Statement 2 | Q is an ideal in R.
A. True, True
B. False, False
C. True, False
D. False, True
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

A ring homomorphism is one-to-one if and only if its kernel is trivial, i.e., contains only the zero element. This is because the kernel of a homomorphism is the set of elements that are mapped to the zero element in the target ring, and if this set contains only the zero element, then the homomorphism is injective (one-to-one).

Therefore, Statement 1 is true.

Statement 2 is false. Q is not an ideal in R. An ideal in a ring R is a subset of R that is closed under addition and multiplication by elements of R. Q is not closed under addition, since the sum of two rational numbers is not necessarily a rational number. For example, 1/2 + 1/3 = 5/6, which is not a rational number.

Therefore, the correct answer is:

C. True, False
D
deepseekr1

The first statement asserts that a ring homomorphism is injective if and only if its kernel is trivial (i.e., {0}). This holds true because, analogous to group homomorphisms, injectivity in ring homomorphisms is equivalent to the kernel containing only the additive identity. The additive structure of rings ensures that a trivial kernel implies injectivity, and vice versa, regardless of whether the rings have unity.

For the second statement, ℚ (the rationals) is not an ideal in ℝ (the reals). While ℚ is an additive subgroup of ℝ, it fails to be closed under multiplication by arbitrary real numbers. For example, multiplying a rational number (e.g., 1) by an irrational number (e.g., √2) yields an irrational number, which is not in ℚ. Thus, ℚ cannot be an ideal in ℝ.

**Answer:** C. True, False
D
gpto1 C D
GPT-4o C. True, False D
llama3.1-70B-Instruct

A
D
llama3.1-405B-Instruct

A ring homomorphism is one-to-one if and only if its kernel is trivial, i.e., contains only the zero element. This is because the kernel of a homomorphism is the set of elements that map to the zero element in the target ring, and if this set contains only the zero element, then the homomorphism is injective (one-to-one).

Therefore, Statement 1 is true.

Statement 2 is false. Q is not an ideal in R. An ideal in a ring R is a subset of R that is closed under addition and multiplication by elements of R. Q is not closed under addition, since the sum of two rational numbers is not necessarily a rational number (e.g., 1/2 + 1/3 = 5/6, which is not a rational number). Therefore, Q is not an ideal in R.

So, the correct answer is:

C. True, False
D
DeepSeek-Coder-V2 C D
Qwen2-72B-Instruct C. True, False D
baichuan4 A. True, True D
doubao C. True, False.

A ring homomorphism is one to one if and only if the kernel is {0}, which is a correct statement. But Q (the set of rational numbers) is not an ideal in R (a general ring) in general, so the second statement is false.
D
minimax C. True, False

Explanation:
Statement 1 is true. A ring homomorphism is one-to-one (injective) if and only if its kernel is trivial, which means the kernel consists only of the zero element of the ring. This is because if there were two distinct elements a and b in the domain such that their images under the homomorphism were the same, then their difference would be in the kernel but not equal to the zero element, contradicting the assumption that the homomorphism is injective.

Statement 2 is false in general. Q (the set of rational numbers) is not an ideal in R (the set of real numbers) because R is a field and the only ideals in a field are {0} and the field itself. Since Q is a proper subset of R, it cannot be an ideal in R.
D
kimi C. True, False

Statement 1 is true. In abstract algebra, a ring homomorphism is a function that preserves the ring operations. If a ring homomorphism is one-to-one (injective), then it means that no two different elements in the domain map to the same element in the codomain. This is equivalent to saying that the only element in the domain that maps to the zero element in the codomain is the zero element itself, which is the definition of the kernel being {0}.

Statement 2 is false. The set of rational numbers, Q, is not an ideal in the ring of real numbers, R. An ideal in a ring is a subset that is closed under the ring operations and contains the additive inverse of every element in the ideal. While Q is closed under addition and multiplication, it is not closed under subtraction in the context of the real numbers (R) because there are real numbers that are not rational, and their additive inverses are not in Q.
D
wenxinyiyan C

Explanation:

Statement 1: A ring homomorphism is one to one if and only if the kernel is {0}.

* This statement is true. By definition, the kernel of a ring homomorphism $f: R \to S$ is the set of all elements in $R$ that are mapped to $0$ in $S$. If the kernel contains only $0$, then no two distinct elements in $R$ can map to the same element in $S$ (otherwise their difference would be in the kernel but not equal to $0$). Conversely, if the homomorphism is one-to-one, then only $0$ can map to $0$ in $S$, so the kernel is {0}.

Statement 2: Q is an ideal in R.

* This statement is false. $\mathbb{Q}$ (the set of rational numbers) is not an ideal in $\mathbb{R}$ (the set of real numbers) when considered as rings with the usual operations of addition and multiplication. An ideal $I$ in a ring $R$ must satisfy that for all $r \in R$ and $i \in I$, both $ri$ and $ir$ are in $I$. However, taking $r = \sqrt{2} \in \mathbb{R}$ and $i = 1 \in \mathbb{Q}$, we see that $ri = \sqrt{2} \notin \mathbb{Q}$. Therefore, $\mathbb{Q}$ is not an ideal in $\mathbb{R}$.
D
zhipu The correct answer is C.

Here's the reasoning:

**Statement 1:** "A ring homomorphism is one to one if and only if the kernel is {0}."
- This statement is true. In ring theory, a ring homomorphism \( f: R \to S \) is injective (one to one) if and only if its kernel \( \ker(f) \) is {0}. This is a standard result in ring theory.

**Statement 2:** "Q is an ideal in R."
- This statement is false. The rational numbers \( \mathbb{Q} \) are not an ideal in the ring of integers \( \mathbb{Z} \). An ideal in a ring must be a subset of the ring, and \( \mathbb{Q} \) is not a subset of \( \mathbb{Z} \).

Therefore, the correct choice is C. True, False.
D
gpto1 C D
deepseekv3 The correct answer is **C. True, False**.

### Explanation:
- **Statement 1**: A ring homomorphism is one-to-one if and only if the kernel is {0}.
This is **true**. By definition, a ring homomorphism is injective (one-to-one) if and only if its kernel is the trivial ideal {0}.

- **Statement 2**: Q is an ideal in R.
This is **false**. The set of rational numbers \( \mathbb{Q} \) is not an ideal in the ring of real numbers \( \mathbb{R} \). An ideal must be closed under multiplication by any element of the ring, but multiplying an irrational number by a rational number does not necessarily result in a rational number.

Thus, the correct choice is **C. True, False**.
D