# Definition:Mutatis Mutandis

## Definition

**Mutatis mutandis** is Latin for **what needs changing having been changed**.

It can be used in place of words like *analogously* and *similarly*, and expresses that an argument can be applied to a new situation in an intuitive fashion.

For example the proof of Union is Associative can be made into that for Intersection is Associative by **mutatis mutandis**.

In this case, this comes down to replacing $\cup$ by $\cap$, and $\lor$ by $\land$.

In particular, the essential flow of the argument was not changed in adapting the proof.

## Also defined as

*The term is often used when some work but no imagination is demanded of the reader.*- -- Ephraim J. Borowski and Jonathan M. Borwein:
*Dictionary of Mathematics*: Entry:**mutatis mutandis**

- -- Ephraim J. Borowski and Jonathan M. Borwein:

## Sources

- 1989: Ephraim J. Borowski and Jonathan M. Borwein:
*Dictionary of Mathematics*... (previous) ... (next): Entry:**mutatis mutandis**