setlike

Setlike is an adjective used in mathematics, logic, and computer science to describe objects or collections that resemble mathematical sets in structure or behavior. In informal use, a setlike collection is one that supports a recognizable membership relation and, often, operations that depend only on which elements are contained, not on any ordering of those elements.

In mathematics and logic, the term is applied to constructions that behave similarly to sets within a given framework but do not necessarily satisfy all axioms required to be a set in that framework. A setlike object may be manipulated in ways analogous to sets, such as forming unions or testing membership, while remaining outside the formal notion of a set, for example if the framework distinguishes between sets and larger classes.

In computer science, setlike data structures implement an interface that supports membership tests, addition and removal of elements, and set operations such as union, intersection, and difference. They typically enforce element uniqueness and usually do not preserve any particular order. Setlike collections are common in programming libraries as abstractions for deduplication and fast membership checks.

Overall, the term is context-dependent and not tied to a single formal theory. It serves as a descriptive label across disciplines for objects that behave like sets in relevant respects while potentially lacking other set-theoretic properties. See also set, class, proper class, data structure.