Comparing notions of approximation.
In this note we discuss some drawbacks of some approaches to the classification of NP-complete optimization problems. Then we analyze the Theory of Analytical Computational Complexity to gain some insight about the notions of approximation and approximate algorithms. We stress the different roles played by these notions within the theories of Analytical and Algebraic Complexity. We finally outline a possible strategy to capture a more useful notion of approximation which is inspired by some results...