# P18: [Proof Group D] CKM theta_12 — HUA POLYNOMIAL PROOF

**Category:** proof_prompt | **Kernel:** PHAT v1.27.5 | **Status:** PENDING

## Prompt

CKM theta_12 — HUA POLYNOMIAL PROOF
Prove that the Cabibbo angle arises from the Hua polynomial on the Shilov boundary of the exceptional domain: theta_12 = arcsin(1/sqrt(20)) = arcsin(sqrt(5)/10) ~ 12.921 degrees. Show sqrt(5) arises from the 5-cycle structure of the Hua polynomial. Compare to PDG theta_12 ~ 13.04 degrees (deviation -0.913%). Assess whether sub-leading Hua corrections close the gap. Rate peer-review status. #SuperGrokTOE #CKMmatrix #Cabibbo