We introduce the notion of a universal obstruction of a graph parameter with respect to some quasi-ordering relation on graphs. Universal obstructions may serve as a canonical obstruction characterization of the approximate behaviour of graph parameters. We provide an order-theoretic characterization of the finiteness of universal obstructions and, when this is the case, we present some algorithmic implications on the existence of fixed-parameter algorithms.

翻译：我们引入了图参数相对于某种图拟序关系的通用障碍概念。通用障碍可作为图参数近似行为的规范障碍刻画。我们给出了通用障碍有限性的序理论刻画，并在此情形下，论述了其对固定参数算法存在的若干算法学意义。