Negative Cycles inWeighted Digraphs
نویسندگان
چکیده
1. Is there a constant ratio approximation algorithm for the nni distance on unweighted evolutionary trees or is the O(log n)-approximation the best possible? 2. Is the linear-cost subtree-transfer distance NP-hard to compute on weighted evolutionary trees if leaf labels are not allowed to be non-unique? 3. Can one improve the approximation ratio for linearcost subtree-transfer distance on weighted evolutionary trees?
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تاریخ انتشار 2008