Abstract type is a generic type parameter comprising - type constructor

Abstract type is a generic type parameter comprising - type constructor;

 

Abstract type definitions can not be directly used as a variable type;

You must be concrete;

 

It is a generic type constructor.

 

+ Constructor parameter type = specific type of space;

 

= + Particular type of generic type parameter space.

 

Generic concept of field type, and the interface, the abstract concepts same level;