Algorithmic information theory
Algorithmic information theory
A Theory of Program Size Formally Identical to Information Theory
Journal of the ACM (JACM)
Recursively enumerable reals and Chaitin &OHgr; numbers
Theoretical Computer Science
Randomness and Recursive Enumerability
SIAM Journal on Computing
Visualization 2001 Conference (Acm
Visualization 2001 Conference (Acm
Computability and Randomness
Phase transition between unidirectionality and bidirectionality
WTCS'12 Proceedings of the 2012 international conference on Theoretical Computer Science: computation, physics and beyond
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Chaitin [G. J. Chaitin, J. Assoc. Comput. Mach. , vol. 22, pp. 329---340, 1975] introduced his Ω number as a concrete example of random real. The real Ω is defined as the probability that an optimal computer halts, where the optimal computer is a universal decoding algorithm used to define the notion of program-size complexity. Chaitin showed Ω to be random by discovering the property that the first n bits of the base-two expansion of Ω solve the halting problem of the optimal computer for all binary inputs of length at most n . In the present paper we investigate this property from various aspects. It is known that the base-two expansion of Ω and the halting problem are Turing equivalent. We consider elaborations of both the Turing reductions which constitute the Turing equivalence. These elaborations can be seen as a variant of the weak truth-table reduction, where a computable bound on the use function is explicitly specified. We thus consider the relative computational power between the base-two expansion of Ω and the halting problem by imposing the restriction to finite size on both the problems.