The notation is used to indicate an interval from a to c that is inclusive of but exclusive of. Range b-a1 eg. Either or both options can be true.
Including the endpoints of an interval.
There are several different notations used to represent different kinds of inequalities. X is an element of just A and not an element of B. Inclusive definition including or encompassing the stated limit or extremes in consideration or account usually used after the noun. For example the use of the word or in A triangle can be defined as a polygon with three sides or as a polygon with three vertices is inclusive.