Partial Functions from a Domain to a Domain

The value of a partial function from a domain to a domain and a inverse partial function are introduced. The value and inverse function were defined in the article [1], but new definitions are introduced. The basic properties of the value, the inverse partial function, the identity partial function, the composition of partial functions, the 1−1 partial function, the restriction of a partial function, the image, the inverse image and the graph are proved. Constant partial functions are introduced, too.