It is a set of two canons :
Canon of subordinate classes
Canon of coordinate classes
It is concerned with the layout of the classes in arrays and chains in printed schedules.
In arrays and chains, the classes exist in two dimensions, whereas in the schedule these
have to be printed in a single linear order. This canon lays down that while listing,
classes should not be separated from their immediate genus. If we are to arrange in a
filiatory sequence the classes as in the diagram, their order should be :
A, A1, A2, A21, A22, A221, A222, A223, A223, A23, A3, B, C, D, D1, D2, D3.
As another example, if you are making a chart of your joint family lineage, then you
and your brothers/sisters should be listed under your father. Your cousins i.e. children
of your uncle and aunt, which make a collateral arrays with you, should be listed under
their parents. For a filiatory sequence, children should not be separated from their
parents, or species from the genus.
Canons for Filiatory sequence