Are there any hard SAT instances that can be quickly solved?
Is there a special case?
I'm not talking about the whole SAT.
But are there any special cases of hard SAT formulas that can be solved in polynomial time?
We exclude class P resulting from Schaefer's dichotomy theorem for the SAT.
--- Edit:
I may have asked the wrong question:
Are there such special cases known? - "known" - it should be.