Just to make sure that I don't do anything stupid:
There are algorithms for generating all posets of given size up to
isomorphism. So are for lattices and IIRC for vertically indecomposable
lattices. More migth exists or be invented.
Would this be good interface:
Posets_iterator(n, properties=None, width=None, height=None)
that could be used like
Posets_iterator(8, properties=['is_lattice'], width=[3,5])
to get lattices of size 8 with longest antichain of 3, 4 or 5 elements, or
Posets_iterator(10, properties=['is_graded', 'not_selfdual'])
to get graded posets of 10 elements excluding selfduals? Of course many
properties (or combinations of them) would raise NotImplemented or be
implemented with plain generate-and-test method.
--
Jori Mäntysalo
