István Németi, together with Hajnal Andréka founded and lead the Hungarian logic and relativity school. They havemade numerous significant contributions both in logic and in relativity theory and in their interconnections. To celebrate their contributions, on the occasion of István’s 70th birthday, a series of conferences focusing on logic and relativity theory, and beyond, was inaugurated by T...

Successful GPS operations are based on a basic equation: the range measurement equation, |rr(tr) – rs(ts)| = c(tr –ts), in an Earth-centered inertial system. The calculations based this equation show that the correctness of the equation leads to the incorrectness of the two principles of Special Relativity, the principle of relativity and the principle of the constancy of the speed of light. Th...

We show that models with deformations of special relativity that have an energy-dependent speed of light have nonlocal effects. The requirement that the arising nonlocality is not in conflict with known particle physics allows us to derive strong bounds on deformations of special relativity and rule out a modification to first order in energy over the Planck mass.

We present a definition of time measurement based on high energy photons and the fundamental length scale and show that, for macroscopic time, it is in accord with the Lorentz transformation of special relativity. To do this we define observer in a different way than in special relativity.

This article investigates an extension of General Relativity based upon a class of lifted metrics on the cotangent bundle of space-time. The dynamics of the theory is determined by a fixed section of the cotangent bundle, representing the momentum of a fluid flow, and Einstein’s equations for the fluid applied to the induced space-time metric on the submanifold of the cotangent bundle defined b...

Here an introduction to Wesley’s neomechanics is presented. It is shown to produce some of the same results as Special Relativity but without both the mathematical and philosophical basis of that subject. As with other work in which results associated with General Relativity are obtained without recourse to the fundamental bases of that subject, so here too the preeminent place afforded Special...

The invariance of the speed of light in all inertial frames is shown to be an inevitable consequence of the relativity principle of special relativity contrary to the view held by Hsu and Hsu in taiji relativity where the speed of light is no longer a universal constant.The present approach is not only new but also much simpler than the existing approaches .