Exponentiation
When it is a positive integer, the exponent indicates how many copies of the base are multiplied together. For example, . The base appears times in the repeated multiplication, because the exponent is . Here, is the "base", is the "exponent", and is the "power" or, more specifically, "3 raised to the 5th power".
Ordered exponential
where the term "n" = 0 is equal to 1 and
where formula_3 is a higher-order operation that ensures the exponential is time-ordered: any product of "a"("t") that occurs in the expansion of the exponential must be ordered such that the value of "t" is increasing from right to left of the product; a schematic example:
This restriction is necessary as products in the algebra are not necessarily commutative.