Table of Contents - 20.43.19.2. Non-unital rings ("rngs")

According to Wikipedia, "... in abstract algebra, a rng (or pseudo-ring or
non-unital ring) is an algebraic structure satisfying the same properties as
a [unital] ring, without assuming the existence of a multiplicative
identity. The term "rng" (pronounced rung) is meant to suggest that it is a
"ring" without "i", i.e. without the requirement for an "identity element"."
(see https://en.wikipedia.org/wiki/Rng_(algebra), 6-Jan-2020).