Pebbles and Branching Programs for Tree Evaluation

@article{Cook2012PebblesAB,
  title={Pebbles and Branching Programs for Tree Evaluation},
  author={S. Cook and P. McKenzie and D. Wehr and M. Braverman and R. Santhanam},
  journal={ArXiv},
  year={2012},
  volume={abs/1005.2642}
}
We introduce the <i>tree evaluation problem</i>, show that it is in <b>LogDCFL</b> (and hence in <b>P</b>), and study its branching program complexity in the hope of eventually proving a superlogarithmic space lower bound. The input to the problem is a rooted, balanced <i>d</i>-ary tree of height <i>h</i>, whose internal nodes are labeled with <i>d</i>-ary functions on [<i>k</i>] = {1,..., <i>k</i>}, and whose leaves are labeled with elements of [<i>k</i>]. Each node obtains a value in [<i>k</i… Expand
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