The Structure of Logarithmic Advice Complexity Classes

A nonuniform class called here Full-P/log, due to Ko, is studied. It corresponds to polynomial time with logarithmically long advice. Its importance lies in the structural properties it enjoys, more interesting than those of the alternative class P/log; speciically, its introduction was motivated by the need of a logarithmic advice class closed under polynomial-time deterministic reductions. Several characterizations of Full-P/log are shown, formulated in terms of various sorts of tally sets with very small information content. A study of its inner structure is presented, by considering the most usual reducibilities and looking for the relationships among the corresponding reduction and equivalence classes deened from these special tally sets.