“…4 is the smallest dimension where exotic diffeomorphisms exist. After a long hiatus following Ruberman's pioneering work [45,46] exotic diffeomorphisms of 4-manifolds have attracted significant interest in recent studies through the advancement of families Seiberg-Witten theory [10,26,31,33,23,25]. One of the main results in Ruberman [46] was to prove that the group of (components of) exotic diffeomorphisms can be infinitely generated for some 4-manifolds.…”