Let a and b belong to some extension field of F and let b be algebraicover F. Prove that [F(a, b):F(a)] ≤ [F(a, b):F].

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

Let a and b belong to some extension field of F and let b be algebraic
over F. Prove that [F(a, b):F(a)] ≤ [F(a, b):F].

Expert Solution
Step 1

Given: A field F and a and b belong to some extension field of F and b is algebraic over F.

To prove: Fa,b : FaFa,b : F.

Step 2

It is given that b is algebraic over F.

Let fx be the minimal polynomial for b over F.

Then, fxFax and hence b is algebraic over Fa.

Thus, Fa,b is a linear space of finite dimension over Fa.

Clearly, a,bFab.
This implies that, Fa,bFab  . . . (1)

Now since, bFa,b  and  FaFa,b, therefore, FabFa,b  . . . (2)

Hence, from (1) and (2) we have,
Fab=Fa,b

Also, Fa,b : Fa=Fab : Fa<.

steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
Ring
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,