double bubble conjecture

A double bubble is pair of bubbles which intersect and are separated by a membrane bounded by the intersection. The usual double bubble is illustrated in the left figure above. A more exotic configuration in which one bubble is torus-shaped and the other is shaped like a dumbbell is illustrated at right (illustrations courtesy of J. M. Sullivan). In the plane, the analog of the double bubble consists of three circular arcs meeting in two points. It has been proved that the configuration of arcs meeting at equal 120° angles) has the minimum perimeter for enclosing two equal areas (Alfaro et al. 1993, Morgan 1995).

apple surface | bubble | circle-circle intersection | double sphere | isovolume problem | sphere-sphere intersection