From: Martin Mares Date: Sat, 3 May 2008 19:31:25 +0000 (+0200) Subject: Removed most refs from the Epilogue. X-Git-Tag: printed~15 X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=df4ba9a6e6de4f6b8ffb52e48a76856ef23252ee;p=saga.git Removed most refs from the Epilogue. --- diff --git a/epilog.tex b/epilog.tex index cbdc03a..2bfe779 100644 --- a/epilog.tex +++ b/epilog.tex @@ -8,14 +8,13 @@ We have seen the many facets of the minimum spanning tree problem. It has turned out that while the major question of the existence of a~linear-time MST algorithm is still open, backing off a~little bit in an~almost arbitrary direction leads to a~linear solution. This includes classes of graphs with edge -density at least $\lambda_k(n)$ for an~arbitrary fixed~$k$ (Corollary \ref{lambdacor}), -minor-closed classes (Theorem \ref{mstmcc}), and graphs whose edge weights are -integers (Theorem \ref{intmst}). Using randomness also helps (Theorem \ref{kktavg}), -as does having the edges pre-sorted (Example \ref{sortededges}). +density at least $\lambda_k(n)$ for an~arbitrary fixed~$k$, +minor-closed classes, and graphs whose edge weights are +integers. Using randomness also helps, as does having the edges pre-sorted. If we do not know anything about the structure of the graph and we are only allowed -to compare the edge weights, we can use the Pettie's MST algorithm (Theorem -\ref{optthm}). Its time complexity is guaranteed to be asymptotically optimal, +to compare the edge weights, we can use the Pettie's MST algorithm. +Its time complexity is guaranteed to be asymptotically optimal, but we do not know what it really is --- the best what we have is an~$\O(m\timesalpha(m,n))$ upper bound and the trivial $\Omega(m)$ lower bound. @@ -28,7 +27,7 @@ to study the complexity of MST decision trees. However, aside from the propertie mentioned in Section \ref{dtsect}, not much is known about these trees so far. As for the dynamic algorithms, we have an~algorithm which maintains the minimum -spanning forest within poly-logarithmic time per operation (Corollary \ref{dynmsfcorr}). +spanning forest within poly-logarithmic time per operation. The optimum complexity is once again undecided --- the known lower bounds are very far from the upper ones. The known algorithms run on the Pointer machine and we do not know if using a~stronger @@ -38,7 +37,7 @@ For the ranking problems, the situation is completely different. We have shown linear-time algorithms for three important problems of this kind. The techniques, which we have used, seem to be applicable to other ranking problems. On the other hand, ranking of general restricted permutations has turned out to balance on the -verge of $\#P$-completeness (Theorem \ref{pcomplete}). All our algorithms run +verge of $\#P$-completeness. All our algorithms run on the RAM model, which seems to be the only sensible choice for problems of inherently arithmetic nature. While the unit-cost assumption on arithmetic operations is not universally accepted, our results imply that the complexity of our algorithm