Ustcon

Some articles on ustcon:

Symmetric Turing Machine - Idea About Why USTCON Is SL-complete
... The most important Complete Problem is the USTCON, Lewis and Papadimitriou by their definition showed that USTCON is complete for SL class ... They constructed a nondeterministic machine for USTCON, and they made a lemma for converting this machine into Symmetric Turing Machine ... accepted using a symmetric Turing machine is logspace reducible to USTCON as from the properties of the symmetric computation we can view the special configuration as the undirected edges of the graph ...
SL (complexity)
... is the complexity class of problems log-space reducible to USTCON (undirected s-t connectivity), which is the problem of determining whether there exists a path between two vertices in an undirected graph ... USTCON is a special case of STCON (directed reachability), the problem of determining whether a directed path between two vertices in a directed graph exists ... Because USTCON is SL-complete, most advances that impact USTCON have also impacted SL ...
SL (complexity) - Important Results
... algorithms such as depth-first search and breadth-first search which solve USTCON in linear time and space ... It's also not difficult to show that USTCON, and so SL, is in NL, since we can just nondeterministically guess at each vertex which vertex to visit next in order to discover a path ... for SL, however, was Savitch's theorem, proved in 1970, which provided an algorithm that solves USTCON in log2 n space ...