Exercises: Extension fields
Exercise
Show that every finite field is of prime-power order, that is, it has a prime-power number of elements.
Here are some hints which play a role:
Hint 3:
In essence, here's the flow and how your linear algebra basics come into play:
1. Finite field (your main object):
You start with a finite field.
2. Characteristic p and Prime Field `ZZ_p` (Step 1):
You discover that this finite field must have a prime characteristic p , and thus
contains a subfield isomorphic to `ZZ_p `. This `ZZ_p` is your base field.
3. Vector Space (Step 2 & Hint 2): Because every element of F is algebraic over `ZZ_p` (Hint 2),
this means F can be seen as a vector space over `ZZ_p`.
A vector space needs a set of vectors (the elements of F) and a set of scalars
(the elements of `ZZ_p`) , and operations (addition and scalar multiplication) that satisfy
certain axioms. Since F is a field , these properties naturally hold.
Because F is finite, it must be a finite-dimensional vector space. Let this dimension be n.
Question
Considering a finite field F as a vector space over its prime field `ZZ_p` , which statement
correctly identifies the vectors and scalars in this context:
A) The elements of the finite field F are the vectors , and the elements of the prime field
`ZZ_p` are the scalars.
B) The elements of the prime field `ZZ_p` are the vectors , and the elements of the finite field
are the scalars
?