问题


There is a single choice question about abstract algebra. Answer the question by replying A, B, C or D.
Question: Statement 1 | If R is a ring and f(x) and g(x) are in R[x], then deg (f(x)+g(x)) = maximum (deg f(x), deg g(x)). Statement 2 | If F is a field then every ideal of F[x] is principal.
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

D
D
deepseekr1

The first statement claims that the degree of the sum of two polynomials is the maximum of their degrees. However, if their leading terms cancel (e.g., \(f(x) = x\) and \(g(x) = -x\) in a ring where \(-1\) exists), the degree of the sum becomes less, making Statement 1 **False**.

The second statement asserts that every ideal in \(F[x]\) is principal when \(F\) is a field. Since \(F[x]\) is a principal ideal domain (PID) when \(F\) is a field, Statement 2 is **True**.

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

Statement 1 | If R is a ring and f(x) and g(x) are in R[x], then deg (f(x)+g(x)) = maximum (deg f(x), deg g(x)). This statement is false. For example, if f(x) = x and g(x) = -x, then deg (f(x)+g(x)) = 0, but maximum (deg f(x), deg g(x)) = 1. Statement 2 | If F is a field then every ideal of F[x] is principal. This statement is true. In fact, F[x] is a principal ideal domain (PID), which means that every ideal in F[x] is principal. This is a well-known result in abstract algebra. Therefore, the correct answer is D. False, True.
D
llama3.1-405B-Instruct

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

For the first statement, the degree of f(x) + g(x) is usually less than or equal to the maximum of the degrees of f(x) and g(x), not always equal, so it is false.

For the second statement, it is a well-known result that every ideal of F[x] (where F is a field) is principal, so it is true.
D
minimax A. True, True

Explanation:

Statement 1 is true because in a ring R[x], the degree of the sum of two polynomials f(x) and g(x) is at most the maximum of the degrees of f(x) and g(x). This is because when adding polynomials, we do not combine terms of different degrees, and the leading term (the term with the highest degree) of the sum will be the one with the higher degree of the two leading terms, or it will cancel out if they are the same and opposite in sign.

Statement 2 is also true. In ring theory, it is a well-known result that every ideal in the polynomial ring F[x] over a field F is principal, which means that every ideal I in F[x] can be generated by a single polynomial, i.e., I = (p(x)) for some p(x) in F[x]. This is due to the fact that F[x] is a principal ideal domain (PID), and every PID has the property that all of its ideals are principal.
D
kimi D. False, True

Explanation:
Statement 1 is false. In a ring R, if f(x) and g(x) are in R[x] (the ring of polynomials with coefficients in R), the degree of the sum f(x) + g(x) is not necessarily the maximum of the degrees of f(x) and g(x). The degree of the sum is the maximum of the degrees of f(x) and g(x) only if the leading coefficients of f(x) and g(x) do not cancel each other out when added. If they do cancel, the degree of the sum could be less than the maximum of the degrees of f(x) and g(x).

Statement 2 is true. In a field F, every ideal of F[x] (the ring of polynomials with coefficients in F) is principal. This is a consequence of the fact that F[x] is a principal ideal domain (PID) when F is a field. In a PID, every ideal is generated by a single element, hence every ideal is principal.
D
wenxinyiyan D

Explanation:
Statement 1:
The statement is false. Consider the following counterexample: Let $R$ be any ring, and consider $f(x) = x^2$ and $g(x) = -x^2$ in $R[x]$. Then $f(x) + g(x) = 0$, which has degree $-\infty$ (or undefined, depending on your definition), which is not equal to $\max(\deg f(x), \deg g(x)) = 2$.

Statement 2:
The statement is true. Every ideal $I$ of $F[x]$ is principal because $F[x]$ is a Euclidean domain (since $F$ is a field, $F[x]$ has a Euclidean algorithm). In a Euclidean domain, every ideal is generated by a single element, i.e., it is principal.
D
zhipu D. False, True

Explanation:
- Statement 1 is False: The degree of the sum of two polynomials \( f(x) \) and \( g(x) \) in \( R[x] \) is not necessarily the maximum of the degrees of \( f(x) \) and \( g(x) \). For example, if \( f(x) = x^2 + 1 \) and \( g(x) = -x^2 \), then \( f(x) + g(x) = 1 \), which has degree 0, not the maximum of 2 and 2.

- Statement 2 is True: In a field \( F \), every ideal of the polynomial ring \( F[x] \) is principal. This is a well-known result in ring theory.

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

### Explanation:

1. **Statement 1**:
"If \( R \) is a ring and \( f(x) \) and \( g(x) \) are in \( R[x] \), then \( \deg(f(x) + g(x)) = \max(\deg f(x), \deg g(x)) \)."
This statement is **False**. The degree of the sum of two polynomials is at most the maximum of their degrees, but it is not always equal to the maximum. For example, if \( f(x) = x^2 \) and \( g(x) = -x^2 \), then \( f(x) + g(x) = 0 \), and the degree of the sum is undefined (or sometimes considered \( -\infty \)), not 2.

2. **Statement 2**:
"If \( F \) is a field, then every ideal of \( F[x] \) is principal."
This statement is **True**. In a polynomial ring over a field, every ideal is generated by a single polynomial (a principal ideal). This is a key property of polynomial rings over fields.

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