Space-time code. IV

A successor to quantum mechanics is studied. It extends atomism from matter to physical process and unites certain quantum and relativity principles with stricter finiteness, operationality, and locality. A specific kinematics is given. In it particle processes are discrete networks of elementary quantum processes, monads, of a binary nonunitary kind with specific laws of combination. The general dynamics and several examples are given. The dynamical law is not differential but algebraic. The interpretation involves a small constant time $\tau$. Familiar space-time and field-theory concepts, the Hilbert-space metric, and the Riemannian pseudometric emerge in the approximation $\tau \to 0$, and are semimicroscopic statistical objects. Microscopic Lorentz invariance survives and implies four monads mating two by two. Operationally nonlocal concepts such as energy-momentum, gauge fields, and coordinates are absent from the microscopic theory. In the simplest model all elementary processes transfer both charge and spin, the familiar neutrality of the long-range fields being an average one analogous to that of an electrolyte. $e$, $\gamma$, and $\nu$ codes with correct laws of transformation and propagation are suggested. Electromagnetic, gravitational, weak, and strong interactions are considered within this framework. A heuristic argument estimates $\tau \sim \frac{\hslash }{40}$ GeV. The form of the theory has been determined by internal qualitative requirements and has not been subjected to external quantitative test. The developments needed for this are mentioned.