 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2024/ii/paper-3/10e/b/iii/solution

Codex  0 Created 2026-09-24 Updated 2026-09-25

Across

A ∣ BC

\frac{1}{2} (∣0 ⟩_{A} ∣00 ⟩_{BC} + ∣1 ⟩_{A} ∣11 ⟩_{BC}),

of rank two. Symmetry gives the same rank-two decomposition across

B ∣ A C

and

C ∣ A B

, so the state is entangled across every bipartition.

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