Using oracles for the design of efficient approximation algorithms
نویسندگان
چکیده
We are interested here in oracle techniques for the design of approximation algorithms. Following the classical definition, an oracle is a black box capable of answering correctly and instantaneously any question. Several classical PTAS design techniques can be expressed using oracle formalism (by allowing the algorithm to “guess” some values during the computation). Our objective in this work is to point out the interest of oracle techniques, beyond the design of PTAS. Indeed, questions to the oracle (i.e. guessed values) leading to non polynomial algorithms must also be considered, as the complexity may be exponential, but in a parameter that is supposed to be “small”. Moreover, we aim at showing how it is possible to “degenerate” questions asked to the oracle to derive fast implementations of these interactive algorithms. These ideas will be illustrated on the classical makespan minimization on uniform machines problem (Q||Cmax).
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تاریخ انتشار 2011