Prove F(a,b)=F(a)(b)=F(b)(a) in Field Extensions

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In summary, F(a,b) in field extensions is defined as the smallest field that contains both a and b as elements, denoted as F(a,b) = F(a)(b) = F(b)(a). Proving F(a,b)=F(a)(b)=F(b)(a) is significant because it shows the commutative property of the field extension, and the proof involves demonstrating the same elements and properties on both sides of the equation. An example of F(a,b)=F(a)(b)=F(b)(a) is Q(sqrt(2), sqrt(3)). This proof is also important in Galois theory, which studies the structure of field extensions and has various applications in understanding polynomial roots and equation solvability
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Scherie
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Let E be an extension of F and let a, b belong to E. Prove that F(a,b) =F(a)(b) = F(b)(a).
 
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May we assume that $a$ and $b$ are algebraic over $F$?
 
  • #3
Deveno said:
May we assume that $a$ and $b$ are algebraic over $F$?

Yes
 
  • #4
Pick a basis $\{u_j\}$ for $F(a)$ over $F$, and a basis $\{v_k\}$ for $F(b)$ over $F$.

Consider the set: $\{u_jv_k\}$, and use a dimensional argument.
 

FAQ: Prove F(a,b)=F(a)(b)=F(b)(a) in Field Extensions

How do you define F(a,b) in field extensions?

In field extensions, F(a,b) is defined as the smallest field that contains both a and b as elements. It is denoted as F(a,b) = F(a)(b) = F(b)(a).

What is the significance of proving F(a,b)=F(a)(b)=F(b)(a) in field extensions?

Proving F(a,b)=F(a)(b)=F(b)(a) in field extensions is significant because it shows that the field extension is commutative, meaning that the order in which the elements are multiplied does not affect the result.

What is the proof for F(a,b)=F(a)(b)=F(b)(a) in field extensions?

The proof for F(a,b)=F(a)(b)=F(b)(a) in field extensions involves showing that both sides of the equation have the same elements and satisfy the same properties, such as closure, associativity, and commutativity of addition and multiplication.

Can you give an example of F(a,b)=F(a)(b)=F(b)(a) in field extensions?

One example of F(a,b)=F(a)(b)=F(b)(a) in field extensions is the field extension Q(sqrt(2), sqrt(3)), where Q represents the rational numbers. In this case, F(a,b)=F(a)(b)=F(b)(a)=Q(sqrt(2), sqrt(3)).

How does proving F(a,b)=F(a)(b)=F(b)(a) in field extensions relate to Galois theory?

Proving F(a,b)=F(a)(b)=F(b)(a) in field extensions plays a crucial role in Galois theory, which studies the structure of field extensions. It helps to understand the behavior of roots of polynomials and the solvability of equations, among other applications.

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