Ops, I forget

Rimedio duplicando, anzi triplico:

Dictionary of Definitions of Terms Commonly Used in Math. lectures.

The following is a guide to terms which are commonly used but rarely defined. In the search for proper definitions for these terms we found no authoritative, nor even recognized, source. Thus, we followed the advice of mathematicians handed down from time immortal: "Wing It."

• CLEARLY: I don't want to write down all the "in- between" steps.
• TRIVIAL: If I have to show you how to do this, you're in the wrong class.
• OBVIOUSLY: I hope you weren't sleeping when we discussed this earlier, because I refuse to repeat it.
• RECALL: I shouldn't have to tell you this, but for those of you who erase your memory tapes after every test...
• WLOG (Without Loss Of Generality): I'm not about to do all the possible cases, so I'll do one and let you figure out the rest.
• ONE MAY SHOW: One did, his name was Gauss.
• IT IS WELL KNOWN: See "Mathematische Zeitschrift'', vol XXXVI, 1892.
• IT CAN EASILY BE SHOWN: Even you, in your finite wisdom, should be able to prove this without me holding your hand.
• CHECK or CHECK FOR YOURSELF: This is the boring part of the proof, so you can do it on your own time.
• SKETCH OF A PROOF: I couldn't verify all the details, so I'll break it down into the parts I couldn't prove.
• HINT: The hardest of several possible ways to do a proof.
• BRUTE FORCE (AND IGNORANCE): Four special cases, three counting arguments, two long inductions, "and a partridge in a pair tree."
• SOFT PROOF: One third less filling (of the page) than your regular proof, but it requires two extra years of course work just to understand the terms.
• ELEGANT PROOF: Requires no previous knowledge of the subject matter and is less than ten lines long.
• SIMILARLY: At least one line of the proof of this case is the same as before.
• CANONICAL FORM: 4 out of 5 mathematicians surveyed recommended this as the final form for their students who choose to finish.
• TFAE (The Following Are Equivalent): If I say this it means that, and if I say that it means the other thing, and if I say the other thing...
• BY A PREVIOUS THEOREM: I don't remember how it goes (come to think of it I'm not really sure we did this at all), but if I stated it right (or at all), then the rest of this follows.
• TWO LINE PROOF: I'll leave out everything but the conclusion, you can't question 'em if you can't see 'em.
• BRIEFLY: I'm running out of time, so I'll just write and talk faster.
• LET'S TALK THROUGH IT: I don't want to write it on the board lest I make a mistake.
• PROCEED FORMALLY: Manipulate symbols by the rules without any hint of their true meaning (popular in pure math courses).
• QUANTIFY: I can't find anything wrong with your proof except that it won't work if x is a moon of Jupiter (Popular in applied math courses).
• PROOF OMITTED: Trust me, It's true.

Q: What's the contour integral around Western Europe?
A: Zero, because all the Poles are in Eastern Europe!
Addendum: Actually, there ARE some Poles in Western Europe, but they are removable!

L'ho sostituita con una - penso - migliore.

Top ten things that math and sex have in common

10. Explicit discussions of either topic is a faux pas at most cocktail parties.
9. Historically, men have been in control, but there are now efforts to get women more involved.
8. There are many joint results.
7. Both are prominent on college campuses, and are usually practiced indoors.
6. Most people wish they knew more about both subjects.
5. Both involve long and hard problems, and can produce interesting topology and geometry.
4. Both merit undivided attention, but mathematicians are prone to think about one while doing the other.
3. Saint Augustine was hostile to both, and Alan Turing took an unusual approach to both.
2. Both typically begin with a lot of hard work and end with a great but brief reward.
1. Professionals are generally viewed with suspicion, and most do not earn high pay.

P.