  An integral framed, closed pure n-braid B' in the 3-sphere describes a
positive Artin presentation, if the braid B can be put on a disk with holes
such that each relation describes a positive path and these paths are disjoint.
In the present paper we classify the closed, pure n-braids B' in the 3-sphere,
such that B represents a positive Artin presentation. Also we prove that if
such B describes a positive Artin presentation then B' is strongly invertible.
Such positive Artin presentation give us the fundamental group of closed,
connected and orientable 3-manifolds M, and in fact, by giving an example, we
show that there exist 3-manifolds whose fundamental group does not admit a
positive Artin presentation.
