Topological graphs based on a new topology on $Z^n$ and its applications


Sang-Eon Hana




Up to now there is no homotopy for Marcus-Wyse (for short M-) topological spaces. In relation to the development of a homotopy for the category of Marcus-Wyse (for short M-) topological spaces on Z 2 , we need to generalize the M-topology on Z 2 to higher dimensional spaces X ⊂ Z n , n ≥ 3 [18]. Hence the present paper establishes a new topology on Z n , n ∈ N, where N is the set of natural numbers. It is called the generalized Marcus-Wyse (for short H-) topology and is denoted by (Z n , γ n). Besides, we prove that (Z 3 , γ 3) induces only 6-or 18-adjacency relations. Namely, (Z 3 , γ 3) does not support a 26-adjacency, which is quite different from the Khalimsky topology for 3D digital spaces. After developing an H-adjacency induced by the connectedness of (Z n , γ n), the present paper establishes topological graphs based on the H-topology, which is called an HA-space, so that we can establish a category of HA-spaces. By using the H-adjacency, we propose an H-topological graph homomorphism (for short HA-map) and an HA-isomorphism. Besides, we prove that an HA-map (resp. an HA-isomorphism) is broader than an H-continuous map (resp. an H-homeomorphism) and is an H-connectedness preserving map. Finally, after investigating some properties of an HA-isomorphism, we propose both an HA-retract and an extension problem of an HA-map for studying HA-spaces.