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z). We look at the quadratic form s^2 = t^2 - x^2 - y^2 - zˆ2 where s^2 > 0 (lightcone assumption) With simple symbol ballet t = +/-Sqrt[s^2+x^2+y^2+z^2]. Now, if we impart ANY Lorentz transformation, s is constant. This is the definition of the Lorentz group (conserving the quadratic form s^2). If