REMARKS ON DIGITAL PRODUCTS WITH NORMAL ADJACENCY RELATIONS

REMARKS ON DIGITAL PRODUCTS WITH NORMAL ADJACENCY RELATIONS

To study product properties of digital spaces, we strongly need to formulate meaningful adjacency relations on digital products. Thus the paper [7] firstly developed a normal adjacency relation on a digital product which can play an important role in studying the multiplicative property of a digital fundamental group, and product properties of digital coverings and digitally continuous maps. The present paper mainly surveys the normal adjacency relation on a digital product, improves the assertion of Boxer and Karaca in the paper [4] and restates Theorem 6.4 of the paper [19].