Psarja

Psarja is a term used in Finnish and Estonian mathematical and educational contexts to denote an ordered collection of objects arranged in a sequence, or, more broadly, a mathematical series formed by summing such a sequence. The term functions both as a generic reference to sequences and, in some texts, specifically to the sum of a sequence.

In mathematical analysis, psarja is encountered in discussions of convergence. If a_n denotes the nth term, the psarja communicates either the sequence (a_n) or the series Σ a_n, depending on the author. Classic examples include the geometric psarja Σ r^n (n from 0 to ∞), which converges for |r|<1, and the harmonic psarja Σ 1/n, which diverges.

In education and terminology, psarja is often distinguished from the words sarja (series) or jono (sequence) to avoid ambiguity, though usage varies by country and textbook. Some authors reserve psarja for a sequence, others for a convergent series.

In computer science and data handling, psarja appears as a generic label for a list or array of values that can be indexed, iterated, and transformed. Algorithms operating on psarjat treat them as first-class collections of elements, enabling operations such as mapping, filtering, and aggregation.

See also: sequence, series, convergence, power series, geometric series.