“…For example, let X = R be the set of all real numbers with the usual metric d(x, y) = |x − y| for all x, y ∈ R. The selfmapping T : R → R defined by T x = x 2 − 2 has two fixed points x 1 = −1 and x 2 = 2 . Fixed points of T form the circle C 1 2 , 3 2 = x ∈ R : x − 1 2 = 3 2 . In recent years, the fixed-circle problem and the fixed-disc problem have been studied with this perspective on metric and some generalized metric spaces (see [1, 9, 10, 12-16, 18-20, 23-29] for more details).…”