Bullet Proof

This proof can suffer slings and arrows. It can withstand all manner of flak. It’s a bullet proof proof.

Burden of Proof

In the Pulitzer Prize winning play "Proof" by David
Auburn, dementia is the burden of mathematics professor Llewelyn and his
daughter Catherine who cares for him.

Sound Proof

When the proof is sound, even the loudest critic will be
silenced.

Reproof

To reproof is to criticise.
So when your professor scoffs and hands it back, you have been reproofed
to reprove your proof.

Proofreader

A proofreader is someone who reads proofs – such as a
professor grading Advanced Calc homework.

Goof Proof

Oh no! There’s a goof
in my proof!

Proof of Purchase

L'Hôpital struck a financial arrangement with Johann
Bernoulli in 1694 whereby Johann would instruct L'Hôpital on Johann’s
discoveries in calculus. L'Hôpital
published all of Johann’s results in *L'Analyse
des Infiniment Petits pour l'Intelligence des Lignes Courbes* in 1696. Although L'Hôpital’s book was published
anonymously and thanked Johann in the preface for his many “bright ideas”, the
credit for this great book soon made its way to L'Hôpital.

After L'Hôpital's death in 1704 Johann broke his silence and
announced how *L'Analyse* had come to
be. Unfortunately Johann was not widely
believed at the time. However, history
was set straight in 1922 by the discovery in Basel of an early copy of Johann’s
notes.

Perhaps the greatest of all the results to be found in *L'Analyse* is still known today as
L'Hôpital’s Rule. So it is apt to label
L'Hôpital’s Rule as a “proof of purchase” (purchased proof). The moral of this story – always get a proof
of purchase for your purchased proofs.

Overproof

Hey I got it! This proof is over. Q.E.D.

Notes:

Burden of Proof (fallacy) – assuming a statement true because there
exists no proof that the statement if false

Goof Proof – a process that you can’t mess up, even if you try

Overproof – containing more than 50% alcohol by volume