FUNCTION: drwpst - draw a poset or a bound poset algebra

CALLING SEQUENCE:
drwpst(p);
drwpst(p,l);
drwpst(p,s);
drwpst(p,l,s);

PARAMETERS:
p - a bound poset algebra
l - a list of length p[1] (i.e. the number of points of p)
s - a set of positive integers between 1 and p[1]

SYNOPSIS:

• drwpst uses Maple plot output to draw the Hasse-diagram of p (if p is a poset) or of the underlying poset of p (in case p is a bound poset algebra).

• By default the vertices of the Hasse-diagram are marked by 'o'. If an optional argument s is given, the points corresponding to the elements of s are marked by 'x'.

• By default the vertices of the Hasse-diagram are labelled by the integers 1,... , p[1]. The optional argument l provides a list of labels to use instead of these.

EXAMPLES:

> a:=critical_alge(7,14);

> drwpst(a);

> p:=[9, {[5, 6], [7, 2], [3, 2], [4, 1], [6], [8, 1, 9], [9, 3, 7], [1, 3]}];

> subposet(cr_K[2],p,'incl','img');

> print(img,incl);

> drwpst(p);

> s:=convert(incl,set);

> drwpst(p,s);

> drwpst(p,img);