Quite funny: Proof by...

By way of Natural Blogarithms, we can learn some "useful" proof techniques...

For example:

"Proof by vigorous handwaving: Works well in a classroom or seminar setting.

Proof by forward reference: Reference is usually to a forthcoming paper of the author, which is often not as forthcoming as at first.

Proof by funding: How could three different government agencies be wrong?"

There's much more!