  A knot is a closed loop in space without self-intersection. Two knots are
equivalent if there is a self homeomorphism of space bringing one onto the
other. An arc presentation is an embedding of a knot in the union of finitely
many half planes with a common boundary line such that each half plane contains
a simple arc of the knot. The minimal number of such half planes among all arc
presentations of a given knot is called the arc index of the knot. A knot is
usually presented as a planar diagram with finitely many crossings of two
strands where one of the strands goes over the other. A grid diagram is a
planar diagram which is a non-simple rectilinear polygon such that vertical
edges always cross over horizontal edges at all crossings. It is easily seen
that an arc presentation gives rise to a grid diagram and vice versa. It is
known that the arc index of an alternating knot is two plus its minimal
crossing number. There are 4878 prime alternating knots with minimal crossing
number 13. We obtained minimal arc presentations of them in the form of grid
diagrams having 15 vertical segments. This is a continuation of the works on
prime alternating knots of 11 crossings and 12 crossings.
