부산대학교 도서관

Summary: ``It is shown that when a first integral $I$ of a vector field $\bold X$ is known, the level sets of $I$ resemble bagpipes, and $\bold X$ is asymptotically stable on the skeleton of $I$ (the set where $\nabla I$ vanishes), then the vector field is stable at $\bold 0$ (a singular, not necessarily isolated, zero of $\bold X$). A similar bagpipe configuration is shown to appear among the orbits of the magnetic field created by a set of concurrent straight line wires.''