Even and Odd Pairs of Lattice Paths with Multiple Intersections
نویسندگان
چکیده
Let be the number of ordered pairs of paths in the plane, with unit steps E or N, that intersect k times in which the first path ends at the point (r,n-r) and the second path ends at the point (s,n-s). Let and We study the numbers , , , and , prove several simple relations among them, and derive a simpler formula for than appears in [1].
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ورودعنوان ژورنال:
- J. Comb. Theory, Ser. A
دوره 75 شماره
صفحات -
تاریخ انتشار 1996