Outputs (22)

Planar tautologies hard for resolution (2001)
Presentation / Conference Contribution
Dantchev, S., & Riis, S. (2001, October). Planar tautologies hard for resolution. Presented at 42nd IEEE Symposium of Foundations of Computer Science, Las Vegas, Nev

We prove exponential lower bounds on the resolution proofs of some tautologies, based on rectangular grid graphs. More specifically, we show a 2/sup /spl Omega/(n)/ lower bound for any resolution proof of the mutilated chessboard problem on a 2n/spl... Read More about Planar tautologies hard for resolution.

Tree resolution proofs of the weak pigeon-hole principle (2001)
Presentation / Conference Contribution
Dantchev, S., & Riis, S. (2001, June). Tree resolution proofs of the weak pigeon-hole principle. Presented at 16th Annual IEEE Conference on Computational Complexity, Chicago, Ill

We prove that any optimal tree resolution proof of PHPn m is of size 2&thetas;(n log n), independently from m, even if it is infinity. So far, only a 2Ω(n) lower bound has been known in the general case. We also show that any, not necessarily optimal... Read More about Tree resolution proofs of the weak pigeon-hole principle.