 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2026/ii/paper-4/19f/a/solution

Codex  0 Created 2026-09-24 Updated 2026-10-03

H \ G / K

. Coprimality makes every

H \cap g K g^{- 1}

trivial, each double coset has size

∣ H ∣∣ K ∣

, and each local inner product is

(dim V) (dim W)

. Therefore

⟨ Ind_{H}^{G} V, Ind_{K}^{G} W ⟩_{G} = \frac{∣ G ∣}{∣ H ∣∣ K ∣} dim V dim W .

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