Semichirals and Four Dimensional Geometry

Authors: Ulf Lindström

Preprint number: UUITP-09/15

Semichiral (2,2) sigma models with 4d target space are discussed. A novel description in (1,1) superspace allows an analysis of possible extended supersymmetries. It is argued that a manifest semichiral realization of an extra supersymmetry is only possible for hyperkähler target geometry.