Legal Definitions - Quod erat demonstrandum

Definition: Quod erat demonstrandum is a Latin phrase that means "which was to be demonstrated." It is often abbreviated as Q.E.D. and is used to indicate that the author has just proven their argument.

Illustrative caselaw: For example, in the case of Stupak-Thrall v. U.S., 89 F.3d 1269, 1299 (6th Cir. 1996), the court used the phrase Q.E.D. to indicate that they had just proven their argument.

Explanation: The phrase Q.E.D. is commonly used in academic writing, especially in mathematics and philosophy, to indicate that the author has just demonstrated or proven their argument. It is a way of saying "I have shown what I set out to show" or "I have proven my point." In the example of Stupak-Thrall v. U.S., the court used Q.E.D. to indicate that they had just proven their argument and that there was no further need for discussion or debate.