[dminuoso]

Neither is the case.

Elm semantics were originally loosely based on functional reactive programming in the sense of Conal Elliot, as per the thesis of its author.

Redux on the other hand is just imperative programming folks rediscovering that a state transition can be described as a pure function S -> S, with all the benefits that come along with it. This is as old as lambda calculus itself. Words like reducer are just red herrings.