1

Suppose f(x) $\in$ F[x] is a non-zero irreducible polynomial of degree n < $\infty$ over a field F, then E = F[x]/(f) is a field extension E\F of degree n.

My question is: Can every field extension of F that is of finite degree be constructed in this way?

mattapow
  • 382
  • 3
  • 12

1 Answers1

1

Exactly the simple finite field extensions arise this way. Every separable finite field extension is simple (see the Primitive element Theorem). An example of a finite field extension which fails to be simple is $\mathbb{F}_p(x^p,y^p) \to \mathbb{F}_p(x,y)$. In fact, it has degree $p^2$, but every element has degree $\leq p$.