Stable homotopy groups are a concept in algebraic topology that study the properties of topological spaces through their continuous mappings. These groups are formed by considering the homotopy groups of spheres, which are fundamental objects in topology. The stable homotopy groups are defined as the limit of the homotopy groups of spheres as the dimension goes to infinity. In stable homotopy theory, one often uses the notion of suspension, which involves stretching a space into a higher dimension. This leads to the idea that the stable homotopy groups are invariant under certain transformations, making them useful for classifying spaces. They are denoted as π_n^s and provide insights into the structure of topological spaces and homotopy theory.