The poset Pn is defined as the poset consisting of subsets of 1,...,n where for two subsets X≤Y if and only if X and Y have the same cardinality and if X=x1<...<xk and Y=y1<...<yk we have xi≤yi for i=1,...,k. See for example https://arxiv.org/pdf/1806.06531.pdf .
My question is whether the is an easy way to obtain this poset for a given n with Sage?