Equal diffusion cannot destabilize a stable reaction Jacobian
= Equal diffusion cannot destabilize a stable reaction Jacobian
If both <diffusion> coefficients equal $D$, each spatial mode has matrix $J-Dq^2I$. Its eigenvalues are those of $J$ shifted by the negative real number $Dq^2$. Thus a reaction-stable homogeneous state remains stable under this equal-<diffusion> linear mechanism.