An elementary number is one formalization of the concept of a closed-form number. Roughly speaking, it is a complex number that can be specified using algebraic operations, exponentiation, and logarithms.

Several different kinds of elementary numbers appear in the literature.

An elementary number of Joseph Fels Ritt-algebraic functions), exponential functions, and/or logarithm functions..-elementary function.

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An elementary number of Daniel Richardson is a solution of a special kind of system of exponential polynomial equations.

-algebraic equations respectively special exponential-logarithmic polynomial systems.

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