AGTP-1 Technical Corrigendum: Bijective 2D Implementation Specification

AGTP-1 Version 1.2 is a post-publication implementation corrigendum to the Version 1.1 technical supplement and is anchored to the normative Version 1.0 geometry. It restores the Version 1.0 Equal Earth central meridians (-94.5 degrees and +77.0 degrees), restores the exact published Atlantic/Arctic seam, and restores the south-polar Lambert Azimuthal Equal-Area Antarctic lobe. It also replaces the implementation requirement for a side-channel lobe identifier with a conventional two-dimensional projected coordinate (X, Y). Fixed false-eastings place the lobe images in provably disjoint X intervals, so the inverse identifies its branch from X alone. The deposit includes explicit forward and inverse equations, a global injectivity argument subject to declared map edges and pole singularities, equation-derived graticules, a dependency-free reference implementation, deterministic conformance vectors, numerical validation against PROJ/pyproj, and regression tests. Finite-precision edge ownership is hardened with direct-radian seam evaluation and deterministic canonicalization of numerical representations of the seam, -60 degree boundary, and antimeridian. Version 1.2 supersedes v1.1 numerical implementation artifacts wherever they conflict with the Version 1.0 geometry. AGTP-1 remains independent research and is not EPSG-registered, peer-reviewed, standards-endorsed, or intended for navigation.