== Latin == === Etymology === Attributed by Suetonius in Lives of the Twelve Caesars to Caesar Augustus. The kalends (also written calends) were specific days of the Roman calendar (the first of the month), not of the Greek, and so the “Greek Kalends” would never occur. === Phrase === ad kalendās Graecās (idiomatic) never; "when pigs fly". ==== Descendants ==== Italian: alle calende greche French: aux calendes grecques...

In mathematics, and more specifically in algebra, a ring is an algebraic structure with operations that generalize the arithmetic operations of addition and multiplication. Through this generalization, theorems from arithmetic are extended to non-numerical objects like polynomials, series, matrices and functions. Rings were first formalized as a common generalization of Dedekind domains that occur in number theory, and of polynomial rings and rings of invariants that occur in algebraic geometry and invariant theory. They are also used in other branches of mathematics such as geometry and mathematical...