Determinants of (generalised) Catalan numbers

We show that recent determinant evaluations involving Catalan numbers and generalisations thereof have most convenient explanations by combining the Lindstr\"om-Gessel-Viennot theorem on non-intersecting lattice paths with a simple determinant lemma from [Manuscripta Math. 69 (1990), 173-202]. This approach leads also naturally to extensions and generalisations.Comment: AmS-TeX, 16 pages; minor correction

Bicoloured Dyck paths and the contact polynomial for n non-intersecting paths in a half-plane lattice

In this paper con gurations of n non-intersecting lattice paths which begin and end on the line y = 0 and are excluded from the region below this line are considered