HELP FOR: The CREP dataformat for posets

SYNOPSIS:

• A partially ordered set S is denoted by a pair
  
  [ n, l ]
  
  where n is an integer, the number of elements of S; and l is a list or set
  
  l = [ l₁, ... , l_k ]
  or
  l = { l₁, ... , l_k }
  
  containing information about the Hasse-diagram of S in the following way:
  
  Each entry of l_i of l is a list of positive integers
  
  l_i = [ l_i,1 , l_i,2 ... l_i,mi ]
  
  where { l_i,2 ... l_i,mi } is the set of upper neighbours of l_i,1 in the Hasse-diagram of S, when identifying S with the set { 1, ... , n }.

EXAMPLES:

[6,{[1,2,3],[2,4],[3,4,5],[5],[4,6],[6]}];
[6,{[1,2,3],[2,4],[3,4,5],[4,6]}];
[6,[[1,2,3],[2,4],[3,4,5],[4,6]]];

• Any of these three examples denotes the same poset.

• use the function drwpst to obtain a graphical display of the Hasse-diagram of this poset.