# Talk:L (complexity)

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I appear to be too stupid to figure out how to use the citation system, but the citation is in the references, namely Reingold's paper. If the flag is asking for the fact that the result appeared in October 2004 (which apparently was significant since someone else proved a worse bound a few weeks after Reingold), see http://blog.computationalcomplexity.org/2004/11/undirected-connectivity-in-log-space.html

I just added a section to explain why logspace theory can be usefull outside of the computational world, but I have no practical example, if someone has got any link it could be usefull. (The problem beeing mostly that since examples would be of impossibility, it wouldn't have "real life" use, the logspace algorithm one can see in complexity are of no real world use because of their uge time complexity) —Preceding unsigned comment added by Arthur MILCHIOR (talkcontribs) 23:35, 17 May 2010 (UTC)

## L-complete problems

This page really should have a section on L-complete problems. I will try and add some later when I have more time. However, if anybody wants to beat me to it, here are some:

• Deterministic reachability is perhaps the canonical one.
• Undirected reachability follows from L=SL (and is already in the article).
• SAT(2) (CNF-SAT where each variable occurs at most twice) -- Jan Johannsen. Satisfiability Problems Complete for Deterministic Logarithmic Space. In Proceedings of STACS'2004.
• Planar graph isomorphism -- Samir Datta, Nutan Limaye, Prajakta Nimbhorkar, Thomas Thierauf, and Fabian Wagner. Planar Graph Isomorphism is in Log-Space. In Proceedings of the 2009 24th Annual IEEE Conference on Computational Complexity (CCC '09). — Preceding unsigned comment added by 71.192.228.96 (talk) 14:18, 9 June 2011 (UTC)

## Opinions about the likelihood and consequences of L = P and/or L≠ P

I think the page should also contain opinions on that, and what the equality or inequality would entail. We have that kind of info in the article for the much better known P versus NP problem. Tijfo098 (talk) 23:12, 9 November 2012 (UTC)