{
  "step": "C276",
  "date": "2026-09-24",
  "authorization": "Dean: Proceed after C275 proposal to audit source598 versus assigned translation increment",
  "question": "Do the retained598/600 source relations and17K correspondence determine h-f, or is an additional image-alignment condition required?",
  "source_domain": "Only C269 three cumulative centers and three reflected regular counterparts, with their inherited physical phase pairs",
  "fixed_source_nodes": {
    "S_Shem_closing": -5883,
    "I_Flood_interior_index5": -5285,
    "L_Flood_closing_index7": -5283,
    "R_SP_G3_Flood_start": 3110,
    "P_SP_G2_primary_Noah": 3708,
    "N_SP_G3_primary_Noah": 3710
  },
  "fixed_source_correspondence": 8993,
  "unknowns": {
    "f": "cumulative LXX Flood translation",
    "h": "cumulative LXX Shem translation",
    "alpha": "induced reflected regular Noah map intercept",
    "beta": "induced reflected regular Flood map intercept"
  },
  "maps": {
    "F": "q+f",
    "H": "q+h",
    "G": "-(q+h)",
    "RN": "y+alpha",
    "RF": "-y+beta",
    "T": "q+8993"
  },
  "increment": "delta=h-f is free in the source-only solve; the stored baseline598 is a reference, not an equation in that solve",
  "candidate_additional_condition": "X: H(S)=F(I), equivalently G(S)=M(F(I)); record it as an explicit alignment assumption, not a source duration",
  "cases": [
    "source correspondence and branch transport only",
    "same constraints plus X"
  ],
  "fixed_conventions": [
    "global Mirror M(x)=-x about January AD1",
    "integer source centers with chronological components x+/-1/4",
    "source node identities and roles",
    "regular Gear scope Noah/Shem/Flood only"
  ],
  "domain_policy": "Solve affine systems over Q; retain integer f and h for annual-center/phase-label admissibility. All parameter families stay formal; no value is selected to restore baseline landings.",
  "MT_join_policy": "The unreduced MT join may be written to expose its dependence on delta. It is not imposed in either source-transport case, and the already598-reduced C274 equation must not be used to infer598.",
  "excluded": [
    "No new source event or free-parameter scan",
    "No rerun of the C27136-pair campaign",
    "No extension across all six C271 families in this step",
    "No chart refit or primer reopening",
    "No canonical or graph edit",
    "No new adopted global axis or z-law",
    "No proof that the same increment must apply to other profiles from the LXX rectangle alone",
    "No C277 execution"
  ],
  "supplement": "Preserve C275 corrected LXX8464 observation for awareness only; do not use it in C276 equations",
  "review_type": "Author mathematical/source consistency review only; no new independent-agent review"
}