English

On the number of hypercubic bipartitions of an integer

Combinatorics 2011-06-27 v1

Abstract

We revisit a well-known divide-and-conquer maximin recurrence f(n)=max(min(n1,n2)+f(n1)+f(n2))f(n) = \max(\min(n_1,n_2) + f(n_1) + f(n_2)) where the maximum is taken over all proper bipartitions n=n1+n2n = n_1+n_2, and we present a new characterization of the pairs (n1,n2)(n_1,n_2) summing to nn that yield the maximum f(n)=min(n1,n2)+f(n1)+f(n2)f(n) = \min(n_1,n_2) + f(n_1) + f(n_2). This new characterization allows us, for a given n\natsn\in\nats, to determine the number h(n)h(n) of these bipartitions that yield the said maximum f(n)f(n). We present recursive formulae for h(n)h(n), a generating function h(x)h(x), and an explicit formula for h(n)h(n) in terms of a special representation of nn.

Keywords

Cite

@article{arxiv.1106.4997,
  title  = {On the number of hypercubic bipartitions of an integer},
  author = {Geir Agnarsson},
  journal= {arXiv preprint arXiv:1106.4997},
  year   = {2011}
}

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13 pages