Linked from
The 13 pages that link to Exponent, each with the reason it gives.
PolynomialRelated: Polynomial exponents on variables must be nonnegative integers.
Exponential functionRelated: The input of an exponential function occupies this position.
ExponentiationRelated: The exponent specifies the operation’s power and its extensions.
MonomialRelated: Each variable’s exponent must be a nonnegative integer in a monomial.