👉 Periodids are a type of mathematical function that is not defined for all real numbers. They are named after their characteristic value, which represents the length or duration of an interval in time. In other words, a periodid is a function whose domain is the set of all real numbers and its range is the set of all non-negative integers (0, 1, 2, 3, ...) for which the function is defined. This means that every value in the domain corresponds to exactly one
