Classical and Operator Isominkowskian Unification of General and Special Relativities for Matter and Their Isoduals for Antimatter

We recall that the Minkowskian geometry possesses basic units of space and time which are invariant under the Poincaré symmetry. We then show that, by comparison, the Riemannian geometry possesses space-time units which are not invariant under the symmetries of the Riemannian line element, thus causing evident physical ambiguities. We therefore introduce a novel formulation of general relativity in the isominkowskian geometry which is an axiom-preserving lifting of the conventional Minkowskian geometry but which nevertheless admits all possible Riemannian metrics thanks to a (positive-definite) 4 × 4 generalization of the basic unit. We construct the universal symmetry of the isominkowskian line elements called isopoincaré symmetry, prove that it is locally isomorphic to the conventional Poincaré symmetry, and show that, in this way, conventional Riemannian metrics and related field equations can be expressed with respect to invariant generalized units of space and time. We then show that the isominkowskian geometry and related isopoincaré symmetry permit: I) A classical geometric unification of the general and special relativities for matter into a formulation called isospecial relativity in which the former occurs for generalized units while admitting the latter as a particular case for conventional units; II) A novel operator formulation of gravity for matter based on the abstract axioms of relativistic quantum mechanics, thus showing hope for a possible resolution of the ambiguities in current theories of quantum gravity; and III) A novel classical and operator formulation of antimatter which is an antiautomorphic image of the preceding formulations for matter constructed via a map called isoduality. The experimental validity of the classical isominkowskian formulation of gravity for matter is derived from the preservation of the conventional Einstein’s field equations except for inessential multiplicative terms. The experimental verification of the operator isominkowskian formulation of gravity