Function of arity-2 (possibly expressed as an infix operator)
Which is closed over the set of values that are its arguments/parameters
For a domain (set of input values) which contains a value that converts the function into an identity function when used.
E.g. -
Addition over real numbers (or integers...), becomes an identity function when one arg is 0
Multiplication over real numbers (or integers...), becomes an identity function when one arg is 1
Something along that line?
I guess that makes it useful for a fold/reduce type function where the final result is the same type as the input stream, and the initial value can be identified as a known default.
Function of arity-2 (possibly expressed as an infix operator)
Which is closed over the set of values that are its arguments/parameters
For a domain (set of input values) which contains a value that converts the function into an identity function when used.
E.g. -
Addition over real numbers (or integers...), becomes an identity function when one arg is 0
Multiplication over real numbers (or integers...), becomes an identity function when one arg is 1
Something along that line?
I guess that makes it useful for a fold/reduce type function where the final result is the same type as the input stream, and the initial value can be identified as a known default.