this aspect needs to be investigated further.

A much more detailed discussion of scalar collapse and critical phenomena can be found in other recent reviews [@gun].

Spherical Collapse with General Form of Matter
----------------------------------------------

There is a certain degree of similarity in the collapse behaviour of dust, fluids and scalar fields - in all cases some of the initial data lead to black holes, while other data lead to naked singularities. This would suggest an underlying pattern which is probably characterized, not by the form of matter, but by some invariants of the gravitational field. Hence investigations of collapse which put no restriction on $T_{ik}$ apart from an energy condition should prove useful.

An interesting attempt in this direction was made by Dwivedi and Joshi [@dj2]. They assumed a general $T^{i}_{k}$ obeying the weak energy condition, and also that the collapsing matter forms a curvature singularity. As we noted earlier, in the comoving coordinate system, matter is described by its energy density and the radial and tangential pressures. Along with these three functions, three functions describing the metric enter a set of five Einstein equations, which are coupled with an equation of state in order to close the system. The 