Definition. Computational Problem [problem] A computational problem is a function mapping strings to strings. Example. f(6)=2,3f(6) = \text{2,3} Example. f(z8sst)=errorf\left( \text{z8sst} \right) = \text{error} Note that the definition of a computational problem does not specify how to produce the outputs from the inputs. There is no algorithm here.