Reasoning. Three independent artifact channels are closed. (1) Resolution: a spectral break can be manufactured where resolution changes rapidly with energy; over the dip region the stereo energy resolution is measured to be approximately constant (~20-24%), so the break is not resolution-induced. (2) Aperture: the dip is present in the event energy distribution weighted by E^1.5 — raw data, prior to the Monte Carlo aperture correction — so mis-modeled exposure cannot have created it. (3) Hardware epochs: examining epochs 3-6 separately (best mirror reflectivity and calibration), with projected track length >= 60 degrees and estimated resolution < 25%, the dip appears at the same energy in each. (4) Consistency: a Monte Carlo that takes the stereo spectrum as truth and applies monocular exposure and resolution reproduces the monocular spectrum almost completely below 3 x 10^19 eV — the datasets agree once resolution is accounted for. Together these transfer the feature from possible-instrumental to physical, which matters downstream because the dip anchors the composition-transition interpretation.
Step 6 — validity verdict
approved / checked. Reconstruction — premises: (i) stereo energy resolution is ~constant (20-24%) across the dip region; (ii) the dip is visible in raw E^1.5-weighted event counts before any aperture correction; (iii) the dip appears at the same energy in the best-calibration hardware epochs analyzed separately; (iv) smearing the stereo spectrum with monocular resolution reproduces the monocular spectrum. Load-bearing step: each of (i)-(iii) closes one named artifact channel — a localized break cannot be manufactured by resolution unless resolution varies across the region, nor by exposure mis-modeling if it predates the aperture correction, nor by detector drift if stable across epochs — and (iv) dissolves the mono-stereo tension that would otherwise undercut the dataset. Conditional on the premises, the statement’s conclusion follows; note the statement claims exactly these closures plus consistency (the filename’s stronger “so it is real” gloss is a summary, and reality-modulo-remaining-channels is the fair reading — remaining common-mode systematics attack premise truth, priced in step 8). Traced directly.