Adopted Minkowski physical model of the electromagnetic framework

Adopt as physical assumptions of this framework:

(i) The oriented time-oriented affine Minkowski space $(A,V,\eta ,C^{+})$ used by Laboratory geometry: a restricted inertial chart, its spatial slices and fixed-time fields, together with the conversion constant $c>0$ of Framework-local SI units, the vacuum constants and the exact/measured status of their values, is the spacetime of the framework: its points represent idealized physical events, displacements represent idealized spacetime separations, and the causal classification of the model is the framework's causal structure. In the concrete coordinate realization The Minkowski affine four-space: the form $\eta$, causal cones, frames and Lorentz maps, $A=V={\mathbb{R}}^4$ and $\eta =\mathrm{diag}(-1,1,1,1)$. That supplier uses the symbol $C^{+}$ for the nonzero future causal cone, including null vectors; here, as in the special-relativity model, $C^{+}$ denotes its future timelike subset. The future null boundary vectors retain their separate causal classification.

(ii) The inertial frames and charts of Inertial frames and inertial charts of the affine Minkowski model are the inertial descriptions of the framework, and changes of description are the proper orthochronous isometries adopted in Adopted inertial covariance of the model equations.

(iii) The ideal clock reading rule along future timelike curves and the identification of ideal vacuum light rays with future null straight lines, both with the same constant $c$, are those adopted in Adopted ideal-clock and ideal-vacuum-light interpretation.

(iv) The laboratory description of fields and sources is the restricted inertial chart of Laboratory geometry: a restricted inertial chart, its spatial slices and fixed-time fields, with the spatial Euclidean structure and the SI conventions of Laboratory geometry: a restricted inertial chart, its spatial slices and fixed-time fields and Framework-local SI units, the vacuum constants and the exact/measured status of their values.

Status and scope: the mathematical model defines the geometry and its theorems prove geometric facts only; that physical events are described by the model, that ideal clocks read the stated proper time and that ideal vacuum light follows null straight lines are adopted assumptions, not deductions from experiment or from the mathematical axioms. The special-relativity postulates adopted here do not by themselves select the Maxwell equations, a force law or any matter model: the electromagnetic equations and couplings of this framework are further postulates of it. The framework is classical, flat and non-quantum; gravitational curvature, quantum fields and measurement postulates are outside its scope.