Let formula 16 be a smooth regular convex closed curve. Another example is&colon; Find the smallest area surface filling in a closed curve in space. In the case of a closed curve it is also called a "contour integral". No closed curve can have an asymptote. In a simple closed curve, all turning angles are covered. This self homeomorphism acts on the closed curve along "b". A simple closed curve is also called a Jordan curve. A periodic motion is a closed curve in phase space. Specifically, a closed curve on a plane is needed. Ellipses arise when the intersection of the cone and plane is a closed curve. Let "C" be a simple closed curve on a sphere of radius 1. Provided the closed curve encloses the airfoil, the choice of curve is arbitrary. Let a closed curve be the line along the edge "a" called formula 6. Here, formula 3 is a closed curve in space, formula 4 is the path-ordering operator. The circle is the closed curve of least perimeter that encloses the maximum area.