Just published a Lemma you might find interesting. Would love feedback. You can get it here with the Z3 theorem audit, a CAS audit and an audit for the Heisenberg's derivation. -Abstract Observation is performed using light or its physical equivalent. Light is also what is being observed. Lorentz worked with fields, mathematically inheriting the limitations of field-based assumptions; treating light as a physical object forces the same transformations from geometry alone. Light itself propagates as a finite physical boundary that defines the act of observation. When inertial frames are related by linear reciprocal transformations, the requirement that this boundary propagate consistently in all frames forces a single invariant speed and a specific coupling between space and time. From these constraints, the Lorentz transformation follows. A finite invariant boundary volume then fixes how spatial dimensions scale under relative motion. No spacetime metric, invariant interval, clock construction, nor postulated symmetry is assumed. Lorentz transformations are not assumed but mathematically derived from these requirements. Promoting it to theorem from a dangling assumption https://zenodo.org/records/18522790