Formal proof that the HAL fold operator P-hat generates smoothed BMS supertranslations on S2. Lemma 1: P-hat, d/du = 0 (purely angular operator). Lemma 2: dᵤ C0 = -kappa P-hat C0 (Bondi EOM). Theorem: P-hat = (1-alpha2 nablaS2) ^-1 QBMSGR. Observable modes l less than 10: below 1. 3 percent deviation. Task 2 Step 4 closed. Strominger triangle closes with C0 factor.
Mordecai Gavila Alvarez (Fri,) studied this question.