## Jeffrey C. Lagarias

Dr. Jeffrey C. Lagarias is a Distinguished Member of Technical Staff at
A. T. & T. Bell Laboratories. His research interests include number
theory, theoretical computer science, mathematical programming,
convex geometry, and dynamical systems. He recently showed (with Peter Shor)
that Keller's 1930 conjecture that all tilings of n-space by unit cubes
must contain two cubes having a common facet is false in dimensions 10
and above. (It is true up to dimension 6.) In 1987 he received a Lester R.
Ford award from the Mathematical Association of America.