conformal symmetry.

About conformal symmetry

In physics, a system is said to have conformal symmetry if it is invariant under transformations of spacetime which preserve angles but do not necessarily preserve distances or spacetime intervals, known as conformal transformations. Conformal symmetry is an extension of the more well-known Poincaré symmetry of special relativity which consists of transformations which preserve both angles and spacetime intervals, those being namely rotations, spatial translations, time-translations, and Lorentz transformations. In addition to these symmetries, conformal symmetry encompasses dilations and special conformal transformations. Formally, Poincaré transformations are the isometries of Minkowski spacetime, meaning that they preserve the Minkowski metric, while conformal transformations may rescale it, preserving only its conformal class.