Topics in invariant theory : Sâeminaire d'Algáebre P. Dubreil et M.-P. Malliavin 1989-1990 (40áeme annâee)

These proceedings reflect the main activities of the Paris Séminaire d'Algèbre 1989-1990, with a series of papers in Invariant Theory, Representation Theory and Combinatorics.

It contains original works from J. Dixmier, F. Dumas, D. Krob, P. Pragacz and B.J. Schmid, as well as a new presentation of Derived Categories by J.E.

Björk and as introduction to the deformation theory of Lie equations by J.F.

Pommaret. J. Dixmier: Sur les invariants du groupe symétrique dans certaines représentations II.- B.J.

Schmid: Finite groups and invariant theory.- J.E. Björk: Derived categories.- P. Pragacz: Algebro-Geometric applications of Schur S- and Q-polynomials.- F.

Dumas: Sous-corps de fractions rationnelles des corps gauches de séries de Laurent.- D.

Krob: Expressions rationnelles sur un anneau.- J.F. Pommaret: Deformation theory of algebraic and Geometric structures.- M. van den Bergh: Differential operators on semi-invariants for tori and weighted projective spaces.