“…We say that a digital space is a nonempty, π-connected, symmetric relation set, denoted by (X, π) [11]. It is well known that a digital space [11] includes a digital image (X, k) with digital k-connectivity (i.e., Rosenfeld model) [2,14], a Khalimsky (K-, for brevity) topological space with Khalimsky adjacency [15], a Marcus-Wyse (M-, for short) topological space with Marcus-Wyse adjacency [16], and so forth [5,9,10] (see Section 2 in details).…”