In "Differential Equations, Dynamical Systems and Introduction to Chaos", the norm of the Jacobian matrix is defined to be:
DF_x
= sup DF_x (U), where U is in R^n and F: R^n > R^n and the U = 1 is under the sup.
...U = 1
DF_x (U) is the directional derivative of F in the direction of U. But I don't understand what this definition means?
Thanks
