Obtaining the poset of monotone functions    
   Let $P$ and $Q$ be finite posets. Is there an easy way to obtain the poset (with the natural order) of monotone function from P to Q via Sage? Is it possible to obtain also the poset of injective (or surjective) monotone functions?
Special cases would also be interesting such as when P and Q are lattices or total orders.
 
 
There is
P.intervals_poset()for a specific case.Does Sage only provides a direct way to iterate over all nondecreasing (or monotone) maps between two finite posets ?