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News Release

A Mathematical Milestone:
Double Bubble Conjecture Proved

For further information, contact:
Professor Frank Morgan, Williams College
Telephone: (413) 597-2437
Email: Frank.Morgan@williams.edu

Professor Joel Hass
University of California at Davis
Telephone: (530) 752-1082
Email: hass@math.ucdavis.edu

March 18, 2000

PROVIDENCE, RI---Four mathematicians have proved the Double Bubble Conjecture, which states that the familiar double soap bubble (shown on the right in the figure below) is the optimal shape for enclosing and separating two chambers of air.

In a lecture today at the Rose-Hulman Institute of Technology in Indiana, Frank Morgan of Williams College will announce that he, Michael Hutchings of Stanford University, and Manuel Ritori and Antonio Ros of the University of Granada in Spain have proved this landmark conjecture.

When two round soap bubbles come together, they form a double bubble as on the right in the figure. Unless the two bubbles are the same size, the surface between them bows a bit into the larger bubble. The separating surface meets each of the two bubbles at 120 degrees. This precise shape is now known to have less area than any other shape that encloses and separates the same two volumes of air, even wild possibilities like the one on the left in the figure, in which the second bubble wraps around the first and a tiny separate part of the first wraps around the second.

In 1995 the special case of two equal-sized bubbles was heralded as a major breakthrough when proved with the help of a computer by Hass, Hutchings, and Schlafly. The new proof, involving more possibilities than computers can handle, uses only pencil, paper, and ideas.

In an amazing postscript, a group of undergraduates has extended the theorem to 4-dimensional bubbles. Ben Reichardt of Stanford, Yuan Lai of MIT, and Cory Heilmann and Anita Spielman of Williams, working under Morgan's direction, found a way to extend the proof to 4 dimensional space and to certain cases in dimensions 5 and above.

Standard and Nonstandard Double Bubbles

Computer graphics copyright © 1999 by John M. Sullivan.

The familiar double soap bubble on the right is now known to be the optimal shape for a double chamber. Wild competing bubbles with components wrapped around each other as on the left are shown to be unstable by a novel argument. Computer graphics by John M. Sullivan, University of Illinois, www.math.uiuc.edu/~jms/Images/double/

Double Bubble Conjecture World Wide Web sources:

http://www.math.uiuc.edu/~jms/Images/double/: Pictures of the double soap bubble

http://www.williams.edu/Mathematics/fmorgan/ann.html: Research announcement of proof

http://www.ugr.es/~ritore/bubble/bubble.htm: The complete mathematics paper

http://www.maa.org/news/columns.html: Frank Morgan's Math Chat column and TV show

Founded in 1888 to further mathematical research and scholarship, the 30,000-member American Mathematical Society fulfills its mission through programs and services that promote mathematical research and its uses, strengthen mathematical education, and foster awareness and appreciation of mathematics and its connections to other disciplines and to everyday life.