Suppose I have two finite posets (e.g. constructed with sage.combinat.posets.posets.FinitePoset).
I want to calculate the binary relation which is the composition of the order relations of these posets.
How to do this in Sage?
(I am a Sage novice.)
Not yet, apparently. See Trac 24542 for a general future implementation of binary relations (which is what you'd likely need, since this sort of composition of posets probably usually threatens not to be a poset?).