Key to Notation

The following definitions and conventions apply throughout this section:

`f`	A function, or an operator's left operand (function or array).
`g`	A function, or an operator's right operand (function or array).
`A`	An operator's left argument when an array.
`B`	An operator's right argument when an array.
`X`	The left argument of a function.
`Y`	The right argument of a function.
`R`	The explicit result of a function.
`[K]`	Axis specification.
`[I]`	Index specification.
`{X}`	The left argument of a function is optional.
`{R}←`	The function may or may not return a result, or the result may be shy.

A function can be a primitive function, a system function, a defined (canonical, dfn, or assigned) function, or a derived (from an operator) function.