## EnglishEdit

### EtymologyEdit

Latin *quod erat faciendum* (“what was to have been done”), from Ancient Greek *ὅπερ ἔδει ποιῆσαι* (hoper edei poiēsai).

### InitialismEdit

**QEF**

- “quod erat faciendum”, “what was to have been done” – used to end a mathematical passage other than a proof.

#### Usage notesEdit

Much less used than *QED*. Traditionally used to end passages other than proofs, such as geometric constructions – a “how-to”, not a persuasive argument.