►A latticepath is a directed path on the plane integer lattice
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…For an example see Figure 26.9.2.
►A k-dimensional latticepath is a directed path composed of segments that connect vertices in so that each segment increases one coordinate by exactly one unit.
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►It follows that also equals the number of partitions of into parts that are less than or equal to .
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►It is also equal to the number of latticepaths from to that have exactly vertices , , , above and to the left of the latticepath.
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