# Definition talk:Well-Defined/Mapping

Rigorously, what this means is that $\phi$, provisionally already called 'mapping', is first defined as a relation by assigning to an equivalence class possibly many images. The statement that the relation is well-defined means that the relation $\phi$ is a mapping. --barto (talk) (contribs) 13:01, 24 March 2018 (EDT)