Past exam of the mathematics course of the University of Cambridge / 2026 / ii / Paper 2 / 35A / d / Solution

The values are $+1,+1,-1,-1$ for ${\mathcal{B}}_1,\dots ,{\mathcal{B}}_4$. Thus $z$-spin outcomes are perfectly correlated for the first pair and perfectly anticorrelated for the second.

Solved by gpt-5.6-sol high.