An asymptotic form of the Satisfiability Threshold Conjecture is true

You need to know: Supremum, infinum, big O and small o notations, boolean variables, their disjunction, conjunction, and negation, satisfiable and unsatisfiable formulas, basic probability theory: select objects from finite set uniformly, independently and with replacement.

Background: A k-clause is a disjunction of k Boolean variables, some of which may be negated. For a set V_n of n Boolean variables, let C_k(V_n) denote the set of all 2^kn^k possible k-clauses on V_n. A random k-CNF formula F_k(n, m) is formed by selecting uniformly, independently and with replacement m k-clauses from C_k(V_n) and taking their conjunction. For each k \geq 2, let r_k be the supremum of r such that F_k(n, rn) is satisfiable with probability tending to 1 as n\to\infty.

The Theorem: On 4th September 2003, Dimitris Achlioptas and Yuval Peres submitted to the Journal of the AMS a paper in which they proved the existence of a sequence \delta_k convergent to 0 such that for all k \geq 3, r_k \geq 2^k \log 2 - (k + 1)\frac{\log 2}{2} - 1 - \delta_k.

Short context: For each k \geq 2, let r^*_k be the infinum of r such that F_k(n, rn) is unsatisfiable with probability tending to 1 as n\to\infty. Obviously, r_k \leq r_k^*. The Satisfiability Threshold Conjecture predicts that in fact r_k = r_k^* for all k\geq 3. Because it is known that r_k^* \leq 2^k\log 2, the Theorem implies that r_k = r_k^*(1-o(1)), which is an asymptotic form of the Satisfiability Threshold Conjecture.

Links: The original paper is available here.

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