Typos
One more typo.
Merge branch 'PPC13'
Fix claim about theoretical difficulty of NP problems
Improve sentences about linear time complexity
Remove imprecise statement "in reasonable delay"
Merge remote-tracking branch 'bruno/LUnivPaper'
An example of LUniv compression
Fix typo
Fix "Prop." and "Algo.".
Fix a preposition
LUniv: Separate equations on page 3
Merge remote-tracking branch 'bruno/LUnivPaper'
PCC: proof as tree/proof as DAG
PCC: add slide.tex (oups)
Merge branch 'develop' of https://github.com/Jogo27/ResK-GSoC into LUnivPaper
Make it clearer what happens when an active literal is not valent
Make the example's description more detailed
Move example to a better location
Make the introduction more focused on the resolution calculus and less focused on automated deduction tools