Question

In: Advanced Math

Theorem: Let K/F be a field extension and let a ∈ K be algebraic over F....

Theorem: Let K/F be a field extension and let a ∈ K be algebraic over F. If deg(mF,a(x)) = n, then

1. F[a] = F(a).

2. [F(a) : F] = n, and

3. {1, a, a2 , ..., an−1} is a basis for F(a).

Solutions

Expert Solution


Related Solutions

Let E/F be a field extension. Let a,b be elements elements of E and algebraic over...
Let E/F be a field extension. Let a,b be elements elements of E and algebraic over F. Let m=[Q(a):Q] and n=[Q(b):Q]. Assume that gcd(m,n)=1. Determine the basis of Q(a,b) over Q.
Let E/F be an algebraic extension and let K and L be intermediate fields (i.e. F...
Let E/F be an algebraic extension and let K and L be intermediate fields (i.e. F ⊆ K ⊆ E and F ⊆ L ⊆ E). Assume that [K : F] and [L : F] are finite and that at least K/F or L/F is Galois. Prove that [KL : F] = [K : F][L : F] / [K ∩ L : F] .
Let E be an extension field of a finite field F, where F has q elements....
Let E be an extension field of a finite field F, where F has q elements. Let a in E be an element which is algebraic over F with degree n. Show that F(a) has q^n elements. Please provide an unique answer and motivate all steps carefully. I also prefer that the solution is provided as written notes.
Prove the theorem in the lecture:Euclidean Domains and UFD's Let F be a field, and let...
Prove the theorem in the lecture:Euclidean Domains and UFD's Let F be a field, and let p(x) in F[x]. Prove that (p(x)) is a maximal ideal in F[x] if and only if p(x) is irreducible over F.
Let k ⊂ K be an extension of fields (not necessarily finite-dimensional). Suppose f, g ∈...
Let k ⊂ K be an extension of fields (not necessarily finite-dimensional). Suppose f, g ∈ k[x], and f divides g in K[x] (that is, there exists h ∈ K[x] such that g = fh. Show that f divides g in k[x].
Problem 3. Let F ⊆ E be a field extension. (i) Suppose α ∈ E is...
Problem 3. Let F ⊆ E be a field extension. (i) Suppose α ∈ E is algebraic of odd degree over F. Prove that F(α) = F(α^2 ). Hints: look at the tower of extensions F ⊆ F(α^2 ) ⊆ F(α) and their degrees. (ii) Let S be a (possibly infinite) subset of E. Assume that every element of S is algebraic over F. Prove that F(S) = F[S]
If K is finite and F is an algebraic closuer of K, then the Galois group...
If K is finite and F is an algebraic closuer of K, then the Galois group Aut F over K is abelian. Every element of Aut F over K has infinite order.
Let f(x)∈F[x] be separable of degree n and let K be the splitting field of f(x)....
Let f(x)∈F[x] be separable of degree n and let K be the splitting field of f(x). Show that the order of Gal(K/F) divides n!.
(3) Let V be a vector space over a field F. Suppose that a ? F,...
(3) Let V be a vector space over a field F. Suppose that a ? F, v ? V and av = 0. Prove that a = 0 or v = 0. (4) Prove that for any field F, F is a vector space over F. (5) Prove that the set V = {a0 + a1x + a2x 2 + a3x 3 | a0, a1, a2, a3 ? R} of polynomials of degree ? 3 is a vector space over...
Let f be an irreducible polynomial of degree n over K, and let Σ be the...
Let f be an irreducible polynomial of degree n over K, and let Σ be the splitting field for f over K. Show that [Σ : K] divides n!.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT