Let be a finite and simple graph with vertex set , and let be a two-valued function. If is an integer and for each , where is the closed neighborhood of is a signed -dominating function on . A set of distinct signed -dominating functions on with the property that for each , is called a signed -dominating family (of functions) on , where is an integer. The maximum number of functions in a signed -dominating family on is the signed -domatic number on , denoted by .