finalwhere

Finalwhere is a term used in some mathematical and computer science discussions to refer to the final location, index, state, or element in a finite set or process that satisfies a given condition. It is typically described as the rightmost or last position at which a predicate holds.

Formal notion and definition: Consider a finite sequence a1, a2, ..., an and a predicate P that can be evaluated at each index or element. The finalwhere of P in the sequence is defined as the largest i in {1, ..., n} such that P(ai) is true, when such an i exists. If no index satisfies P, finalwhere is usually left undefined or noted as none (depending on context). Variants may use 0-based indexing or define the result as a special sentinel value.

Examples: Let the sequence be (2, 5, 3, 9) and P(x) be “x > 3.” The indices with P true are i = 2 and i = 4, so the finalwhere is 4. If P(x) were “x < 0,” the finalwhere would be undefined for this sequence.

Variations and notes: In some contexts, finalwhere assumes a monotone predicate or a specific data structure, which can influence how it is computed (for instance, via binary search on monotone predicates). The term remains informal and is not part of a standardized terminology set; its precise meaning can vary between authors.

See also: rightmost true, last occurrence, last index, end position.