f_{\mu}=\frac{\beta_{\mu}\psi\xi_{_{g}}}{\cosh^{2}\psi\xi}
,\hspace{2em}
\xi=\xi_{_{T}}x^{0}+\xi_{_{S}}\sqrt{(x^{1})^{2}+(x^{2})^{2}+(x^{3})^{2}}
,\hspace{2em}
\beta_{\mu},\:\xi_{_{g}}},\:\xi_{_{T}},\:\xi_{_{S}}\rightarrow constant
Is this f_{\mu} soliton ?