Circuits and Sparse Sets
Johannes Köbler, Uwe Schöning, Jacobo Torán · Birkhäuser Boston eBooks · 1993
Some of the concepts introduced in the previous chapters like Turing reducibility or the games between a Prover and a Verifier, can be interpreted as different ways to study the complexity of a problem supposing that one can get some external “help” or information. In the case of the Turing reducibility this external help is the information contained in an oracle set or function, while in the case of games between a Prover and a Verifier, the external information can be anything the Prover sends.