Valid Names for Functions and Expressions

An expression or function name must be either

1.

a single character (other than a standard constant), with or without a subscript

- or -

2.

a custom Math Name (which does not allow subscripts).

Expression names, but not function names, may include an arbitrary number of primes. Variables named with primed characters should be used with caution, as they are open to misinterpretation in certain contexts.

• Examples of valid expression names include α_X, f₁₂₃, g_θ, Ω_∞, e₂, r^′′, Waldo (custom name).

• Examples of valid function names include α_X, f₁₂₃, g_θ, Ω_∞, e₂, sin, Alice (custom name).

• Examples of invalid function names include ΔF (two characters), π, e (standard constants), f_ab (two-character subscript), r^′ (reserved for derivative).

In the example of function names, the subscript on f₁₂₃ is properly regarded as the number one hundred twenty three, not ``one, two, three.''

Note    Subscripts on expression or function names must be numbers or single characters.