eFxy

eFxy is a label that appears in a variety of technical contexts to denote an expression involving two input variables, x and y, often with an exponential or composition component. There is no single, widely accepted definition of eFxy; different authors use it as shorthand in examples, exercises, or informal notation. In practice, the meaning of eFxy is determined by how the symbols are defined in a given source, and readers should look for an explicit definition in that context.

One common reading in mathematics is that eFxy stands for the exponential of a two-variable function F, written as e^{F(x,y)}. In this interpretation F is a real-valued function of x and y, and eFxy inherits the properties of F through the exponent. In other contexts, eFxy may denote a two-variable function named eFxy, where the letters e and F are parts of a nomenclature rather than specific operations, and x and y are the inputs.

Because of the variety of uses, any appearance of eFxy should be accompanied by a precise definition of the components involved (the domain, the function F, and how x and y enter). The notation is most common in informal notes, teaching examples, or software documentation where compact labeling aids readability. See also exponential function, two-variable functions, and notation in mathematics to place eFxy within broader conventions.