Trace-determinant stability criterion (source code)

= Trace-determinant stability criterion

For a real $2\times2$ <Jacobian matrix> $J$, both <eigenvalues>[eigenvalue] have negative <real part> exactly when
$$
\operatorname{tr}J<0
\quad\hbox{and}\quad
\det J>0.
$$
The <linearization stability theorem> then makes a hyperbolic equilibrium locally <asymptotic stability>[asymptotically stable].