Bracket notation (InstanceTopic, 3)
From Hi.gher. Space
Bracket notation uses pairs of brackets [], parentheses (), and chevrons <> to indicate the three bracketopic products max, rss, and sum respectively. This defines the implicit equation of a shape as f(x, ...) = k, where to find the function f, you replace each pair of brackets with the relevant function, and k is a constant determining the size of the shape (usually 1). For example, the implicit equation for the crind, which has bracket notation ([xy]z), is rss(max(x,y),z) = k.
Note that bracket notation can also be read as SSC notation, in which case it remains valid and still represents the same shape.