 It is a consequence of this definition that \(A \leq_T B\) just in case \(\chi_A(x)\) coincides with the (total) \(B\)-computable function given by \(\phi^{B}_e(x)\) for some index \(e\). For instance if we adopt Turing’s characterization of relative computability, we may think of \(e\) as describing a program for a machine which can consult \(B\) as an oracle. In this case, \(A \leq_T B\) means that it is possible to decide if \(n \in A\) by carrying out the program described by \(e\) on the input \(n\) which may in turn require performing queries to the oracle \(B\) during the course of its computation.