Noncommutative Geometry and Integrable Models
  A construction of conservation laws for $\sigma$-models in two dimensions is generalized in the framework of noncommutative geometry of commutative algebras. This is done by replacing the ordinary calculus of differential forms with other differential calculi and introducing an analogue of the Hodge operator on the latter. The general method is illustrated with several examples. 
A. Dimakis (Goettingen) and F. Mueller-Hoissen (Goettingen)