Rings - Euclidean rings, polynomial rings, unique factorization domains, quotient rings, ideals, maximal ideals - One Line Questions
1.
In the ring Z, the ideal generated by 6 and 9 is: —
(3)
2.
Which of the following is an example of a maximal ideal in Z? —
(p) where p is prime
3.
In the ring of polynomials F[x], what is the ideal generated by the polynomial x^2 + 1 over the field of real numbers R? —
(x^2 + 1)
4.
What is the degree of the zero polynomial? —
Undefined or -∞
5.
Which of the following is an irreducible element in the ring of integers Z? —
7
6.
Which of the following is a unit in the ring of integers Z? —
-1
7.
Let R be an integral domain. If R is a PID, then R is also: —
A UFD
8.
In a ring R, what is an ideal I? —
A subset of R that is an additive subgroup and absorbs multiplication from R.
9.
In a UFD, an element is irreducible if and only if it is: —
Prime.
10.
In an integral domain, what is the relationship between irreducible and prime elements? —
All prime elements are irreducible, but not vice-versa.
11.
Consider the polynomial ring R[x]. If R is a UFD, then R[x] is: —
A UFD, but not necessarily a PID.
12.
What is a principal ideal in a ring R? —
An ideal generated by a single element.
13.
What is a prime ideal in a commutative ring R with unity? —
An ideal I such that if ab ∈ I, then a ∈ I or b ∈ I.
14.
What is a maximal ideal in a commutative ring R with unity? —
An ideal I such that if J is an ideal with I ⊆ J ⊆ R, then J = I or J = R.
15.
If R is a commutative ring with unity and I is a maximal ideal, then R/I is: —
A field
16.
If R is a commutative ring with unity and I is a prime ideal, then R/I is: —
An integral domain
17.
What is a Unique Factorization Domain (UFD)? —
An integral domain where every non-zero, non-unit element can be uniquely factored into irreducible elements, up to order and units.
18.
What is the relationship between maximal ideals and prime ideals in a commutative ring with unity? —
Every maximal ideal is prime.
19.
What is the relationship between PIDs and UFDs? —
Every PID is a UFD.
20.
Which of the following statements about ideals is FALSE? —
In a commutative ring with unity, every prime ideal is maximal.
21.
A UFD is an integral domain where every non-zero, non-unit element can be factored into: —
Irreducible elements uniquely, up to order and units.
22.
What is the defining property of a Euclidean domain? —
It possesses a Euclidean function (or norm) that allows for a division algorithm.
23.
Which property guarantees that an integral domain is a UFD? —
Every non-zero non-unit element has a unique factorization into irreducibles.
24.
In a principal ideal domain (PID), every prime ideal is also: —
Maximal
25.
Let I be an ideal in a commutative ring R with unity. R/I is an integral domain if and only if I is: —
Prime
26.
Consider the ring Z. The ideal (0) is: —
Prime but not maximal.
27.
The quotient ring Z_n is a field if and only if: —
n is prime.
28.
Consider the ring Z. Is the ideal (2) a maximal ideal? —
29.
Is the ring of polynomials F[x] over a field F a UFD? —
Yes, it is a UFD.
30.
Consider the ring Z[i] (Gaussian integers). Is it a Euclidean domain? —
Yes, with the norm function N(a+bi) = a^2 + b^2.
31.
A principal ideal domain (PID) is an integral domain where every ideal is: —
Principal
32.
The First Isomorphism Theorem for Rings states that if φ: R → S is a surjective ring homomorphism, then R/ker(φ) is isomorphic to: —
S
33.
Which condition is necessary for a ring R to be a Euclidean domain? —
R must be commutative and have a unity element.
34.
What is the ideal generated by the polynomial x in the ring R[x]? —
The set of polynomials with zero constant term.
35.
For a commutative ring R with unity, the ideal I is maximal if and only if: —
R/I is a field.
36.
For a commutative ring R with unity, the ideal I is prime if and only if: —
R/I is an integral domain.
37.
In the context of Euclidean rings, the 'division algorithm' refers to: —
For any a, b in R with b != 0, there exist q, r such that a = bq + r with r = 0 or φ(r) < φ(b).
38.
The ring of polynomials F[x] over a field F is a Euclidean domain with the Euclidean function being: —
The degree of the polynomial.
39.
Which of the following is NOT necessarily a Euclidean domain? —
The ring of Eisenstein integers, Z[ω]
40.
Which of the following is a UFD? —
The ring of integers Z
41.
What is the quotient ring R/I formed by an ideal I in a ring R? —
The set of cosets of I in R, with appropriate ring operations.
42.
Which property is shared by all Euclidean domains? —
They are principal ideal domains.
43.
If R is a commutative ring with unity, and I is an ideal, when is R/I a field? —
When I is a maximal ideal.
44.
Consider the ring Z_4. The ideal I = (2) = {0, 2}. Is I a maximal ideal in Z_4? —
Yes, because Z_4/(2) is isomorphic to Z_2, which is a field.
45.
Let R = Z_6. The ideal I = (3) = {0, 3}. Is I a maximal ideal in Z_6? —
Yes, because Z_6/(3) is isomorphic to Z_2, which is a field.
46.
In the ring Z[x], is the ideal (x) a maximal ideal? —
No, because Z[x]/(x) is isomorphic to Z, which is not a field.
47.
Let R = Z and I = 4Z. The quotient ring Z/4Z is isomorphic to: —
Z_4
48.
Which of the following is a UFD but not a PID? —
Z[x]
49.
Which of the following is NOT a polynomial ring? —
Z_n
50.
In a Euclidean domain, every non-zero non-unit element is: —
Irreducible