The definition for a simple curve according to Stewart, Calculus Early Transcendental (9th edition) is:
A curve that does not intersect itself anywhere between its endpoints.
But then the book said on pg.1158 that $C$ in fig.8 is a simple curve and that the y axis diivides it into 2 simple curves, could someone explain to me why it is not a simple curve according to the given definition please?
Here is the figure below:
