410(3): Invariance of the Square of the Time Infinitesimal
This is an important new idea defined in Eq. (10), which is simply a rewriting of the familiar four invariance (2). Eq. (10) leads to the precession (15) due to time dilatation and length contraction. Note carefully that this is accurately measurable experimentally and exists in the absence of de Sitter rotation. The latter leads to the novel invariance equation (28) and the new universal law of all observable precessions, Eq. (30).