Logical depth

Logical depth is a measure of complexity for individual strings devised by Charles H. Bennett based on the computational complexity of an algorithm that can recreate a given piece of information. It differs from Kolmogorov complexity in that it considers the computation time of the algorithm with nearly minimal length, rather than the length of the minimal algorithm.
Formally, in the context of some universal computer formula_1 the logical depth of a string formula_2 to significance level formula_3 is given by formula_4 the running time of the fastest program that produces formula_2 and is no more than formula_3 longer than the minimal program.