Generating trees and proper Riordan Arrays
نویسندگان
چکیده
16 other words, the ending point is not situated above the main diagonal x = y. When the path never goes above this diagonal, we simply call it an underdiagonal path. Shapiro's paths 8] are another interesting kind of paths. These paths are characterized by the fact that the northeast steps on the main diagonal may have diierent colours from the northeast steps on the other diagonals. In other words, we have (; ;) colours as in the paths above, but on the main diagonal 0 colours (0 6 =) are used for northeast steps. The paths made up of n steps and ending at distance k from the main diagonal (the distance is measured along the x? or y?axis) can be counted by means of the following
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عنوان ژورنال:
- Discrete Mathematics
دوره 218 شماره
صفحات -
تاریخ انتشار 2000