科研之友
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摘要
We present a unified extension of alternating subsets to k-combinations of {1, 2, ... , n} containing a prescribed number of sequences of elements of the same parity. This is achieved by shifting attention from parity-alternating elements to pairs of adjacent elements of the same parity. Enumeration formulas for both linear and circular combinations are obtained by direct combinatorial arguments. The results are applied to the enumeration of bit strings.
- 出版日期2013-7
