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Modeling the structure

Our program supports three different models to represent the structure of the system. First we can model the structure by a partition of the set of unknowns. Second, we can use a tuple of partitions, so that every equation can have a different partition. The most general model is a set structure, illustrated hereafter.

In (8) we show a supporting set structure for an example.

 

Based on we formally calculate the number as

 

The sets underneath the formula (9) indicate the sets associated to the linear systems that determine the start solutions. We proved that actually bounds the number of isolated complex solutions using a homotopy continuation argument. Note that the total degree equals nine for this example.

The program provides for all models heuristic procedures for setting up a partition, tuple of partitions or set structure. Restricting to partitions, the user may ask to generate all partitions. Up to dimension eight, this is not too exhaustive in computational time. Following [26], the Bézout numbers are calculated efficiently by evaluating permanents.



Jan Verschelde
Thu Nov 21 10:50:01 MET 1996