0 & 1 \\
 0 & 0 & \lambda_{31} & 1 & 0 \\
 0 & 0 & \lambda_{33} & 0 & 1 \\
\end{array}
\right),\end{aligned}$$ standardized trait and method factors, with uncorrelated method factors, $$\begin{aligned}
    \Phi_1 =  \kbordermatrix{
     &   \eta_1 &\eta_2 & \eta_3 & \xi_1& \xi_2\\
 \eta_1  &  1 & \rho_{12} & \rho_{13}  & 0& 0\\
 \eta_2 &  \rho_{12} & 1 & \rho_{23} & 0& 0\\
 \eta_3  &  \rho_{13} & \rho_{23} &1 & 0& 0\\
  \xi_1 &  0& 0& 0 & 1& 0\\
 \xi_2  &  0& 0& 0 & 0& 1\\
}, &\;& 
 \Phi_2 =  \kbordermatrix{
     &   \eta_1 &\eta_2 & \eta_3 & \xi_1& \xi_3\\
 \eta_1  &  1 & \rho_{12} & \rho_{13}  & 0& 0\\
 \eta_2 &  \rho_{12} & 1 & \rho_{23} & 0& 0\\
 \eta_3  &  \rho_{13} & \rho_{23} &1 & 0& 0\\
  \xi_1 &  0& 0& 0 & 1& 0\\
 \xi_3  &  0& 0& 0 & 0& 1\\
},\end{aligned}$$ and error variance matrices $$\begin{aligned}
    \Psi_1 = \text{diag}(\psi_{1},\psi_{ 2},\psi_{3},\psi_{ 4},\psi_{5},\psi_{6}), &\;& 
    \Psi_2 = \text{diag}(\psi_{1},\psi_{7},\psi_{3},\psi_{8},\psi_{5},\psi_{9}).\end{aligned}$$

The Jacobian of this model, $\boldsymbol{\Delta}_{\text{\sc{sbmtmm}}}$, is given in Equation \[eq:delta-ctum\] in the Appendix. When applying a computer algebra system such as Mathematica [@Mathematica] to this problem, we obtain a non-trivial nullspace *only* in the 