A galois lattice shows the distribution of industries by taking the set of all cities
(yellow node) and breaking them into sets according to attributes (green and red nodes)
which may intersect (pottery is found ONLY in cities producing paper) or may note (sets
that intersect at the lower node 7). When city sizes are added as attributions (previous
link to slides with green background in a time series), the addition of extra information
makes the lattice more complex.The discrete structure diagrams give a direct idea of
combinatorial complexity.