On regularity concepts in variational analysis

The paper offers a new approach that allows unifying various regularity concepts used in variational analysis: the most fundamental local regularity triad (openness at a linear rate – metric regularity – Aubin property), the calmness–subregularity pair, directional regularity, upper Lipschitz continuity etc. The main new element of the approach is the appearance of a new parameter which is a set to which regularity is related (whence the term “relative regularity” used in the paper to name the general property). The main emphasis is put on characterizations of relative regularity and its stability with respect to additive perturbations of the (generally set-valued) mapping. A discussion of a relative extension of strong regularity properties concludes the paper.