Eugepae

Eugepae, Latin for "Hooray!" or "Well done!", is commonly used in place of the more traditional Q.E.D. at the end of a mathematical proof. [http://mathworld.wolfram.com/QED.html]

Example

The following is a proof of the Pythagorean Theorem: [http://mathforum.org/isaac/problems/pythagthm.html]

c² + 2ab = (a + b)²
c² + 2ab = a² + 2ab + b²
c² = a² + b²
EUGEPAE

Etymology and Early Use

The phrase 'Eugepae' originated with a common phrase during the Roman Republic during times of great happiness, such as the Pax Romana. It formed as a combination of two words, 'Eughe,' which was an onomatopoeia from natural calls and cheers made in Latin and 'epaequos,' which roughly translates as 'great happiness and solace in times of great strife', detailing Rome's victories over worthy adversaries such as the Gauls, the Carthaginians, and the Visigoths. However, this derivation is disputed. Other linguists believe that the term eventually derived from similar Greek roots expressing similar petulant approval or the most optimal delight, the most popular of these words being Eureka. However, this was the time before the late Latin grammar concepts had been completed, such as the ablative absolute and the supine. Its usage in mathematics serves to emphasize the tremendous feeling of satisfaction obtained via completion of a proof.

Modern Philosophy

In the European Renaissance, mathematical books were typically written in Latin, and phrases such as "Eugepae!" were often used to triumphantly laud one's proofs.

Currently, it has become so symbolic of irrefutable logic that "Eugepae!" is occasionally used in non-mathematical contexts as well to intensify assertions; in this context (as in all) it has little connection with rigorous deduction, and is more tongue-in-cheek.

References