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Counterexample

Is this true?

Every extension of degree n has a Galois group of order n

No — it is false.

The counterexample

Q(23)/Q\mathbb{Q}(\sqrt[3]{2})/\mathbb{Q} has degree 3 but only the identity automorphism

Why it fails

The extension is not normal — the other cube roots are not real. Order = degree only for Galois extensions.

Go deeper· Explained in full in Galois correspondence and the standard groups· Asked in CSIR NET December 2025· From Rings and Fields › Galois theory essentials

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