Double Bubble

The planar double bubble (three circular arcs meeting in two points at equal 120° Angles) has the minimum Perimeter for enclosing two equal areas (Foisy 1993, Morgan 1995).

See also Apple, Bubble, Double Bubble Conjecture, Sphere-Sphere Intersection

References

Campbell, P. J. (Ed.). Reviews. Math. Mag. 68, 321, 1995.

Foisy, J.; Alfaro, M.; Brock, J.; Hodges, N.; and Zimba, J. ``The Standard Double Soap Bubble in $\Bbb{R}^2$ Uniquely Minimizes Perimeter.'' Pacific J. Math. 159, 47-59, 1993.

Morgan, F. ``The Double Bubble Conjecture.'' FOCUS 15, 6-7, 1995.

Peterson, I. ``Toil and Trouble over Double Bubbles.'' Sci. News 148, 101, Aug. 12, 1995.