range problem
A range problem is a weakened form of a search problem. It consists of two functions and (the lower and upper bounds) and a linear ordering on the ranges of and . A Turing machine
solves a range problem if, for any , the machine eventually halts with an output such that .
For example, given any function with range in and any , the strong range problem is given by lower bound and upper bound (note that is passed the length of , not the value, which need not even be a number).