We study the possibility of correctly identifying , from the smooth galaxy density field of the PSCz flux limited catalogue , high density regions ( superclusters ) and recovering their true shapes in the presence of a bias introduced by the coupling between the selection function and the constant radius smoothing .
We quantify such systematic biases in the smoothed PSCz density field and after applying the necessary corrections we study supercluster multiplicity and morphologies using a differential geometry definition of shape .
Our results strongly suggest that filamentariness is the dominant morphological feature of PSCz superclusters .
Finally , we compare our results with those expected in three different cosmological models and find that the \Lambda CDM model ( \Omega _ { \Lambda } = 1 - \Omega _ { m } = 0.7 ) performs better than \Omega _ { m } = 1 CDM models .

Keywords : cosmology : theory - galaxies : general - large-scale structure of universe - Infrared : galaxies