Let
F be a field. Prove that if σ is an isomorphism of F(α1, . ....
Let
F be a field. Prove that if σ is an isomorphism of F(α1, . . . ,
αn) with itself such that σ(αi) = αi for i = 1, . . . , n, and σ(c)
= c for all c ∈ F, then σ is the identity. Conclude that if E is a
field extension of F and if σ, τ : F(α1, . . . , αn) → E fix F
pointwise and σ(αi) = τ (αi)...
Define a+b=a+b -1 and a*b=ab-(a+b)+2 Assume that (Z, +,*) is a
ring. (a) Prove that the...
Define a+b=a+b -1 and a*b=ab-(a+b)+2 Assume that (Z, +,*) is a
ring. (a) Prove that the additative identity is 1? (b) what is the
multipicative identity? (Make sure you proe that your claim is
true). (c) Prove that the ring is commutative. (d) Prove that the
ring is an integral domain. (Abstrat Algebra)
4. (30) Let C be the ring of complex numbers,and letf:C→C be the
map defined by...
4. (30) Let C be the ring of complex numbers,and letf:C→C be the
map defined by
f(z) = z^3.
(i) Prove that f is not a homomorphism of rings, by finding an
explicit counterex-
ample.
(ii) Prove that f is not injective.
(iii) Prove that the principal ideal I = 〈x^2 + x + 1〉 is not a
prime ideal of C[x].
(iv) Determine whether or not the ring C[x]/I is a field.
Consider the ring R = Z∞ = {(a1,a2,a3,···) : ai ∈ Z for all
i}.
It...
Consider the ring R = Z∞ = {(a1,a2,a3,···) : ai ∈ Z for all
i}.
It turns out that R forms a ring under the operations:
(a1,a2,a3,···)+(b1,b2,b3,···)=(a1 +b1,a2 +b2,a3 +b3,···),
(a1,a2,a3,···)·(b1,b2,b3,···)=(a1 ·b1,a2 ·b2,a3 ·b3,···)
Let I = {(a1,a2,a3,···) ∈ Z∞ : all but finitely many ai are 0}.
You may use without proof the fact that I forms an ideal of R.
a) Is I principal in R? Prove your claim.
b) Is I prime in R? Prove your claim....