  To approach the topic of randomness of biased sequences through Kolmogorov complexity, suppose we are given—somehow—any computable probability measure \(\lambda\) over the set of infinite binary sequences (that is, the probability of a given sequence can be approximated arbitrarily well by a recursive function). A sequence \(\sigma\) is \(\lambda\)-incompressible iff for each \(n\), the Kolmogorov complexity of the length \(n\) initial subsequence of \(\sigma\) (denoted \(\sigma_n )\) is greater than or equal to \({-}\log_2 (\lambda(\sigma_n ))\). Where \(\lambda\) is the Lebesgue measure (supplement B.2), it follows that