The Poincaré group, the transformation group of special relativity, being orthogonal, the inverse of a transformation equals its transpose, introducing discrete reflections. This, in turn, violates Einstein's dictum for a group "no less general than that of the continuous transformations of the four coordinates". Specifically, any pair of Euler angles θ k and − θ k are not independent, nor are any pair of boosts v k / c and − v k / c. Available parameters are thus reduced, from the 16 needed to express all transformations in a curved spacetime, per the general principle of relativity, ∂ x /∂ x, to the 10 of the Poincaré group.