### Imre Leader

- on proof
*Part IA, Numbers and Sets*

Quotations:

For all N = "For any natural number in the whole world..."

Counterexample = "If your evil opponent picks some number..."

Solved = "But 'Ah ha'!"

"One bad number kills it."

"Instantly dead..."

"...and we're dead." (these two in context of proofs)

"Proof: well, we're done, aren't we?"

This is a proper contradiction now, not the feeble overkill we had before."

"The proof of this is: 'stare at it a bit'."

"When we want to prove sqrt(2) irrational, what we say is: 'Suppose it is
rational; mumble mumble, contradiction."