Formula_10237

\[\left.\Sigma\left(q^{2}, m^{2}\right)\right|_{q^{2}=m_{\text {физ }}^{2}}=0,\left.\quad \frac{\partial}{\partial q^{2}} \Sigma\left(q^{2}, m^{2}\right)\right|_{q^{2}=m_{\text {физ }}^{2}}=0,\]