Light constraints leave a scale to determine
Linearity and the two light directions constrain space and time to mix. Reciprocity and spatial symmetry then fix a remaining scale, with the positive choice connected to the identity.
Read · Special relativity: from clock operations to electrodynamics · Results
§3 · deriving and inverting the coordinate map
Follow the introduction and all ten sections, including field transformations, finite light complexes, moving mirrors, charge-current transformations, and the electron-force conventions.
Newly authored explanatory preview in modern notation, with editorial and physics review pending. Both the kinematic and electrodynamic halves are treated, but this is not a German transcription, an aligned translation, or a complete critical edition. The source paragraphs, footnotes, acknowledgment, and date-lines are not claimed to be fully represented or reviewed here. Headings and argument units are editorial.
The sideways step needs its own condition
The longitudinal light constraints do not alone determine transverse scale. Enforcing the isotropic light-speed condition on transverse propagation, together with the inverse and positive identity limit, completes the map.