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Séminaire Lotharingien de Combinatoire, B34i (1995), 17pp.

# Christian Krattenthaler

# Counting nonintersecting lattice paths with turns

**Abstract.**
We derive enumeration formulas for families of
nonintersecting lattice paths with given starting and end points and
a given total number of North-East turns. These formulas are important for
the computation of Hilbert series for determinantal and Pfaffian
rings.

The following versions are available:

## Comment by Martin Rubey

Martin Rubey points out that
the argument in the proof of Theorem 4 on pp. 11/12 that a family of
two-rowed arrays with associated permutation not the identity
permutation must contain a crossing point contains an error:
the inequality *A*^{(\si(i+1))}_{1}
-1<= *A*^{(\si(i))}_{1} on page 12 is
not true in general. He provides the following fix: