Three question about how to define things and functions:
1) Should for example Poset({1:[3]}, facade=False) be a subposet of
Poset({1:[2], 2:[3]}, facade=True)? Or should we raise an exception when
is_subposet() is tried for non-facade posets?
(The ticket: http://trac.sagemath.org/ticket/15875 )
2) I will define the two-element lattice to be NOT vertically
decomposable. Complain now, if you want it to be. Definitions seems not to
agree on all papers.
3) I want to have function is_vertically_decomposable() on lattices. But
how about returning the list of "decomposing elements" and the
sublattices. Have one function with arguments? Or two, like on posets we
have is_connected() and connected_components()?
(The ticket: http://trac.sagemath.org/ticket/19123 )
--
Jori Mäntysalo
