Question

In: Advanced Math

Homomorphisms

How many (group) homomorphisms are there from Z20 onto (surjective to) Z8. How many are there to Z8?

Solutions

Expert Solution

If φ : Z20 → Z8 is onto then there is a ∈ Z20, such that φ(a) = 1 ∈ Z8.

This implies that the order |φ(a)| is 8 and divides order of a. But the order of a divides 20.

This implies 8 divides 20, which is a contradiction. There is no homomorpphism from Z20 onto Z8.

 


No such homomorphisms exist from Z20 to Z8.

Related Solutions

Kernal ( Homomorphisms)
Prove that φ : Z ⊕ Z → Z by φ(a, b) = a − b is a homomorphism. Determine the kernel.
Ring Homomorphisms count
How can we determine all ring homomorphisms from Z12 to Z30?
Homomorphisms from Z to Z
How many homomorphisms are there of z into z?  
1.Describe all of the homomorphisms from Z20 to Z40. 2.Describe all of the homomorphisms from Z...
1.Describe all of the homomorphisms from Z20 to Z40. 2.Describe all of the homomorphisms from Z to Z12.
describe group homomorphisms from Q8 into Z8.
describe group homomorphisms from Q8 into Z8.
What is the number of group homomorphisms from z12 to z13?
What is the number of group homomorphisms from z12 to z13?
Find all RING homomorphisms from Z18 to Z18
Find all RING homomorphisms from Z18 to Z18
Find all possible homomorphisms between Z and Z5.
Find all possible homomorphisms between Z and Z5.
Find all ring homomorphisms of Z×Z×Z to Z×Z
Find all ring homomorphisms of Z×Z×Z to Z×Z
Let f : R → S and g : S → T be ring homomorphisms. (a)...
Let f : R → S and g : S → T be ring homomorphisms. (a) Prove that g ◦ f : R → T is also a ring homomorphism. (b) If f and g are isomorphisms, prove that g ◦ f is also an isomorphism.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT