An Inverse-Ackermann Style Lower Bound for the Online Minimum Spanning Tree

نویسنده

  • Seth Pettie
چکیده

We consider the problem of preprocessing an edgeweighted tree T in order to quickly answer queries of the following type: does a given edge e belong in the minimum spanning tree of T [ feg? Whereas the offline minimum spanning tree verification problem admits a lovely linear time solution, we demonstrate an inherent inverseAckermann type tradeoff in the online MST verification problem. In particular, any scheme that answers queries in t comparisons must invest (n log t(n)) time preprocessing the tree, where t is the inverse of the tth row of Ackermann’s function. This implies a query lower bound of ( (n)) for the case of linear preprocessing time. We also show that our lower bound is tight to within a factor of 2 in the t parameter.

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An Inverse-Ackermann Style Lower Bound for the Online Minimum Spanning Tree Verification Problem

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تاریخ انتشار 2002