Questions tagged [resolution]

The tag has no usage guidance.

3 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
9
votes
0answers
129 views

Direct Proof that the Pigeonhole Principle is Hard for Regular Resolution

It is well known that the pigeonhole principle $PHP_n^{n+1}$ is hard for general resolution. The original proof due to Haken is elegant. One first defines a complexity measure for derived clauses, in ...
3
votes
0answers
55 views

Substitution in Resolution Proofs

Let $F = C_1 \wedge C_2\; \wedge ... \wedge\; C_m$ be a unsatisfiable $k$-CNF on variables $x_1,...,x_n$, where $k$ is constant. Let $x_j\rightarrow x_j^1\wedge x_j^2$ be a substitution that replaces ...
2
votes
0answers
179 views

Most general form of SAT which is in P

2-SAT is in P. Additionally, a (CNF) SAT-problem is trivially poly-time solvable if no two expressions can be resolved (via Robinson resolution, ie for every pair of disjunctive clauses, they either ...