Castelnuovo Curves and Unobstructed Deformations.
In the rational cohomology of a 1-connected space a structure of -algebra is constructed and it is shown that this object determines the rational homotopy type.
The aim of this note, which raises more questions than it answers, is to study natural operations acting on the cohomology of various types of algebras. It contains a lot of very surprising partial results and examples.