What is a enclosure notation?

Enclosure notation is a mathematical notation used to describe sets of numbers or values that are bounded within certain limits. It often employs brackets or parentheses to indicate whether the endpoints are included or excluded; for example, [a, b] denotes a closed interval including both endpoints, while (a, b) denotes an open interval excluding them. This notation is commonly used in calculus and set theory to specify domains, ranges, and constraints on variables.