What is the Degree of a Splitting Field for a Polynomial over a Field?

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SUMMARY

The discussion centers on the degree of a splitting field L for a polynomial f in K[x] over a field K. It is established that if the degree of f is d, then the degree of the splitting field L divides d!. The participants explore the cases of reducible and irreducible polynomials, confirming that both cases can be addressed using induction. Specifically, they suggest that for irreducible polynomials, one can consider an intermediate field formed by adjoining a root r of f to K.

PREREQUISITES
  • Understanding of polynomial degrees and their properties
  • Familiarity with splitting fields in field theory
  • Knowledge of induction as a mathematical proof technique
  • Concept of irreducibility in polynomials
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  • Learn about the properties of irreducible polynomials in field extensions
  • Explore the use of induction in algebraic proofs
  • Investigate the relationship between polynomial roots and field extensions
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Homework Statement


Let f in K[x] be a polynomial over a field K. De fine the notion of a splitting field
L of f over K. Show that if deg f = d, then f has a splitting fi eld over K of degree
dividing d!

The Attempt at a Solution


If f is reducible, then this seems true by induction. I'm not sure about the case where f is irreducible over K though.

Thanks for your help.
 
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For anyone keeping score at home, I think the irreducible case is also by induction. Consider an intermediate field made by adjoining a root r of f to K, and then consider L as a splitting field over K(r) of g(x) (where f(x) = (x - r)g(x).)
 
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