Sunday, November 16, 2008

Math Interval Notation

Recently, while writing some documentation, I needed to use some notation to represent a range of numbers. Given my math background, I naturally fell to using mathematics' notation. And, as happened many times in the past, I could not remember the type of brackets used to represent inclusion and exclusion: was it parentheses or square brackets? It turns out that parentheses ( and ) are used for exclusive end points and square brackets [ and ] are used for inclusive end points. Let a and b be enumerable values (more specifically, they are members of a totally ordered set) such that a < b. Then for endpoints a and b,
(a,b) is all values > a and <> [a,b] is all values >= a and <= b (a,b] is all values > a and <= b [a,b) is all values >= a and < b
References [1] Interval (mathematics), Wikipedia, 2008 [2] Set-builder & Interval Notation, Oswego City School District Regents Exam Prep Center, 2008 [3] Totally Ordered Set, Wolfram MathWorld, 2008