Bell-window certificate

Paste the probabilities P(a,b|x,y) from your experiment (2×2×2 scenario). The certifier checks no-signaling, computes the CHSH value in exact arithmetic, and classifies it in the verified window — local (≤2), quantum (≤2√2), or post-quantum (≤4) — emitting a Lean certificate that proves the value by `norm_num`.

Examples:

Context x=0, y=0

P(0,0)P(0,1)P(1,0)P(1,1)

Context x=0, y=1

P(0,0)P(0,1)P(1,0)P(1,1)

Context x=1, y=0

P(0,0)P(0,1)P(1,0)P(1,1)

Context x=1, y=1

P(0,0)P(0,1)P(1,0)P(1,1)

Accepts decimals ("0.426775") or fractions ("3/8"). Each context must sum to 1.