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Connected reorientations of mixed multigraphs
Author(s) -
Shi Weigeng,
Juels Ronald J.
Publication year - 1989
Publication title -
networks
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.977
H-Index - 64
eISSN - 1097-0037
pISSN - 0028-3045
DOI - 10.1002/net.3230190205
Subject(s) - reachability , multigraph , graph , enhanced data rates for gsm evolution , directed graph , combinatorics , mathematics , strongly connected component , space (punctuation) , computer science , discrete mathematics , algorithm , artificial intelligence , operating system
We study here the problem of reorienting the directed edges of mixed multigraphs so as to establish or preserve reachability, which may be destroyed by edge removal. We develop a linear time/space algorithm which tests whether reorienting designated directed edges can reestablish reachability, and which constructs such a reorientation whenever possible. We also develop a linear time/space algorithm which, when reachability has been destroyed by the removal of a single edge, optimally restores reachability through the reversal of selected edges. Finally, we show the reliability of a graph allowing reversals to be twice that of a graph for which reversals are not permitted.