instancesuchC

InstancesuchC is a term sometimes used in computing and formal logic to denote the collection of objects that are instances of a class C and satisfy a given predicate. It is not a formal standard name in mainstream programming languages, but it appears in teaching materials and pseudocode to illustrate the idea of filtering an object's instances by a condition.

In formal notation, instancesuchC is conceptually equivalent to the set of objects x in C for which a predicate P(x) holds, often written in set-builder form as { x ∈ C | P(x) }. The phrase serves as a compact label for describing conditional subsets of a type or class, especially in discussions of constraints, dialects of query languages, or design patterns that emphasize filtering by properties.

Examples help clarify the idea. If C denotes a class Person and P(x) expresses x.age > 18, then instancesuchC corresponds to all Person instances whose age exceeds 18. In practice, many languages implement this concept through filtering or where clauses, such as selecting objects of type C that satisfy a condition, or through pattern matching and type-safe queries.

Relation to related notions includes instance-of relations (which objects are members of C) and set-builder notation in mathematics. InstancesuchC is primarily a descriptive étendue used in pedagogy or specific DSLs, rather than a universal language feature. It highlights the common need to describe subsets of objects by both type and property.