PAGOdA extended with the delta-chase (little bug fix)

Same as before, except for a bug fix introduced in the last commits, regarding a NullPointerException.

PAGOdA extended with the delta-chase

This is a version of PAGOdA extended with a technique, called delta-chase, able to solve efficiently some categories of inputs.
In this version the user must specify a bound D on the parameter of the delta-chase (instead of the parameter itself) and a maximum size N for the materialisation. If N is properly chosen w.r.t. the available main memory, the system will not fill the memory up.

PAGOdA extended with the delta-chase (static depth)

This is a version of PAGOdA extended with a technique, called delta-chase, for dealing with some categories of inputs more efficiently.
The delta-chase takes, among the others, an input d which determines the demand of resources in the worst-case. If d is too big, the delta-chase may fill up the memory and not complete the computation. A solution to this problem will be included in a later release.