p μ = m d x μ d τ = γ m ( c v 1 v 2 v 3 ) = ( E c p i ) {\displaystyle {{p}^{\mu }}=m{\frac {d{{x}^{\mu }}}{d\tau }}=\gamma m\left({\begin{matrix}c&{{v}^{1}}&{{v}^{2}}&{{v}^{3}}\\\end{matrix}}\right)=\left({\begin{matrix}{\frac {E}{c}}&{{p}^{i}}\\\end{matrix}}\right)} es gilt p μ p μ = m 2 c 2 {\displaystyle {{p}^{\mu }}{{p}_{\mu }}={{m}^{2}}{{c}^{2}}}
es gilt
