Anti-self-dual Yang-Mills equations on noncommutative space-time

By replacing the ordinary product with the so-called star -product; one can construct an analog of the anti-self-dual Yang-Mills (ASDYM) equations on the noncommutative R-4. Many properties of the ordinary ASDYM equations turn out to be inherited by the star -product ASDYM equation. In particular, the twistorial interpretation of the ordinary ASDYM equations can be extended to the noncommutative R-4, from which one can also derive the fundamental structures for integrability such as a zero-curvature representation, an associated linear system, the Riemann-Hilbert problem, etc. These properties are further preserved under dimensional reduction to the principal chiral field model and Hitchin's Higgs pair equations. However, some structures relying on finite dimensional linear algebra break down in the star -product analogs. (C) 2001 Elsevier Science B.V. All rights reserved. MSC: 32L25; 58F07; 81E13.