In this paper we consider the properties of linear systems by means of
directed graphs and numerical structures. We also state efficient algorithms
for determining an approximate number of the non-zero terms within
determinants' expressions of the
ir matrices. The stated algorithms make use of
trees representing numerical structures which contains the indices of the nonzero
terms.
This paper yields interesting results used in practical engineering
applications which include linear systems with sparse matrices, for example:
networks, electronic circuits, earth velocities boxes (gearboxes), multi-works
systems ...etc.
