flâneur

Well-defined expression - Wikipedia

en.wikipedia.org · 1,934 words · saved by 1 readers

In mathematics, a well-defined expression or unambiguous expression is an expression whose definition assigns it a unique interpretation or value. Otherwise, the expression is said to be not well defined, ill defined or ambiguous.[1] A function is well defined if it gives the same result when the representation of the input is changed without changing the value of the input. For instance, if 𝑓 takes real numbers as input, and if 𝑓 ( 0.5 ) does not equal 𝑓 ( 1 / 2 ) then 𝑓 is not well defined (and thus not a function).[2] The term well-defined can also be used to indicate that a logical expression is unambiguous or uncontradictory. A function that is not well defined is not the same as a function that is undefined. For example, if 𝑓 ( 𝑥 ) = 1 𝑥 , then even though 𝑓 ( 0 ) is undefined, this does not mean that the function is not well defined; rather, 0 is not in the domain of 𝑓 . Let 𝐴 0 , 𝐴 1 be sets, let 𝐴 = 𝐴 0 ∪ 𝐴 1 and "define" 𝑓 : 𝐴 → { 0 , 1 } as

Well-defined expression - Wikipedia Jump to content From Wikipedia, the free encyclopedia Expression whose definition assigns it a unique interpretation For other uses, see Definition (disambiguation) . In mathematics , a well-defined expression or unambiguous expression is an expression whose definition assigns it a unique interpretation or value. Otherwise, the expression is said to be not well defined , ill-defined or ambiguous . [ 1 ] A function is well defined if it gives the same result when the representation of the input is changed without changing the value of the input. For instance,

related reading