Definitions for "Saddle point"
A point, usually in three-space, that both an attracts and a repels, attracting in one dimension and repelling to another.
A point on a surface that is neither a peak nor a valley, but still has a 0 gradient.
A fixed point that has at least one positive eigenvalue and one negative eigenvalue in its linearization. More generally, a fixed point for which there are trajectories that tend to the fixed point in both positive and negative time.
Keywords:  col