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We examine a definition of the mutual information of two reals proposed by Levin in [5]. The mutual information is

A real is called integer-valued random if no integer-valued martingale can win arbitrarily much capital betting against it. A real is low for integer-valued randomness if no integer-valued martingale recursive in A can succeed on an integer-valued random real. We show that lowness for integer-valued randomness coincides with recursiveness, as is the case for computable randomness.

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The (prefix-free) Kolmogorov complexity of a finite binary string is the length of the shortest description of the string. This gives rise to some 'standard' lowness notions for reals: A is K-trivial if its initial segments have the lowest possible complexity and A is low for K if using A as an oracle does not decrease the complexity of strings by more than a constant factor. We weaken these notions by requiring the defining inequalities to hold up only up to all ∆ 0 2 orders, and call the new notions ∆ 0 2 -bounded K-trivial and ∆ 0 2 -bounded low for K. Several of the 'nice' properties of K-triviality are lost with this weakening. For instance, the new weaker definitions both give uncountable set of reals. In this paper we show that the weaker definitions are no longer equivalent, and that the ∆ 0 2 -bounded K-trivials are cofinal in the Turing degrees. We then compare them to other previously studied weakenings, namely infinitely-often K-triviality and weak lowness for K (in each, the defining inequality must hold up to a constant, but only for infinitely many inputs). We show that ∆ 0 2bounded K-trivial implies infinitely-often K-trivial, but no implication holds between ∆ 0 2 -bounded low for K and weakly low for K.