Universal zero-one k-law

Resumo

The limit probabilities of first-order properties of a random graph in the Erdős–Rényi model G(n, n^−α), α ∈ (0, 1), are studied. For any positive integer k ≥ 4 and any rational number t/s ∈ (0, 1), an interval with right endpoint t/s is found in which the zero-one k-law holds (the zero-one k-law describes the behavior of the probabilities of first-order properties expressed by formulas of quantifier depth at most k).Moreover, it is proved that, for rational numbers t/s with numerator not exceeding 2, the logarithm of the length of this interval is of the same order of smallness (as n→∞) as that of the length of the maximal interval with right endpoint t/s in which the zero-one k-law holds.