Presymmetry of classical relativistic fields

The physical act of accelerating observation instruments has an obvious counterpart in Newtonian physics: It is the transformation induced by (x→, t)→(x→+12a→t2, t). In special relativity, a theoretical counterpart for physical acceleration has been introduced only for a small subset of measurement procedures, such as clocks and yardsticks, but not for such instruments as accelerometers. We propose a general theoretical counterpart for physical accelerations in Minkowski space. In the algebra O of observation procedures, it induces automorphisms, not of O but of a point subalgebra Ox,O that is associated to a single point x. From the postulates of presymmetry, we deduce a generalized version of Newton's second law; an acceleration-invariant subset (x|x0=0)Oxc of instant observation procedures provides complete predictive power. The main technical contribution of the paper is the introduction of a topological algebra O in which local subsets associated to a single point are proper (although unbounded) subalgebras, whose automorphisms are discussed.