Quantum groups emerged in the latter quarter of the 20th century as, on the
one hand, a deep and natural generalization of symmetry groups for certain
integrable systems, and on the other as part of a generalization of geomet
ry itself powerful enough to make sense in the quantum domain. Just as the
last century saw the birth of classical geometry, so the present century se
es at its end the birth of this quantum or noncommutative geometry, both as
an elegant mathematical reality and in the form of the first theoretical p
redictions for Planck-scale physics via ongoing astronomical measurements.
Noncommutativity of space-time, in particular, amounts to a postulated new
force or physical effect called cogravity. (C) 2000 American Institute of P
hysics. [S0022-2488(00)00406-0].