Mathematical relation and Single-valued function

Mathematical relation noun - A relation between mathematical expressions (such as equality or inequality).

Single-valued function and mathematical relation are semantically related. In some cases you can replace phrase "Single-valued function" with "Mathematical relation", this phrases are similar.

Single-valued function noun - Mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function.

Mathematical relation and single-valued function are semantically related. You can use "Mathematical relation" instead a noun phrase "Single-valued function".