In special relativity, many key relationships depart from both Newtonian mechanics and classical theory by a special velocity-dependent term that we can call a Lorentz term , due to its earlier appearance in Lorentzian electrodynamics. A simple introduction to this subject is provided in Special relativity for beginners Special relativity (SR) or the special theory of relativity is the physical theory published in 1905 by Albert Einstein. ... Classical mechanics is a model of the physics of forces acting upon bodies. ... In physics, a classical theory usually refers to a theory that does not obey the principles of quantum mechanics (classical theory vs. ...

This takes the form

or the inverse,

,

, and for brevity is often referred to by the lower-case greek letter "gamma" ( " γ " ).

In special relativity, this term translates between observers' differing perceptions of distance and time, and is associated with the ideas of length contraction and time dilation.

Notes

• "gamma" - Writing the lower-case greek letter γ in place of the above equations can considerably shorten many mathematical descriptions that use special relativity. However, since "gamma" can refer to either of the two relationships above, its use can sometimes introduce a degree of uncertainty over the exact meaning of an equation. A specific meaning for "gamma" can usually be established by context, or can be explicitly defined in the text where the term first appears, but many authors prefer to avoid possible confusion by writing out the Lorentz term in full.