Or, how to hide the fact that you haven't understood a word of a mathematical seminar.
Recently, I attended a mathematical lecture given by a guest speaker where absolutely nobody, except possibly the speaker, had the remotest idea what was going on. Normally, one can absorb at least some of the preliminary definitions and follow, say, the first blackboard full of development of the theory, but on this occasion everyone was completely lost after the first definition. After the speaker had finished over an hour later to an enthusiastic round of applause, the chairman asked for questions, and, of course, there was a deathly and highly embarrassing silence. Then and there I resolved to put together a collection of universal questions for use in such situations. Such questions must sound sensible, but they are designed to cover up the total ignorance of the questioner rather than to elicit information from the speaker.
And what questions they are too! Here are just two examples:
- Can you produce a series of counterexamples to show that if any of the
conditions of the main theorem are dropped or weakened, then the theorem no
[The speaker can almost always do so - if not you may have presented him with a stronger theorem!]
- Isn't there a suggestion of Theorem 3 in an early paper of Gauss?
[The answer to this question is almost always YES!]
I also like the following quotation at the end of the page.
Miscellaneous Methods [for proving theorems] ... reduction ad nauseam, proof by handwaving, proof by intimidation, proof by referral to non-existent authorities, the method of least astonishment, the method of deferral until later in the course, proof by reduction to a sequence of unrelated lemmas (sometimes called the method of convergent irrelevancies) and finally, that old standby, proof by assignment.
- Rome Press 1979 Mathematical Calendar
The proof of their efficacy is left as a trivial exercise for the reader.
[Via a Geomblog commenter.]