A mathematician is asked to design a table. He first designs a table with no legs. Then he designs a table with infinitely many legs. He then spends the rest of his life generalizing results for tables with N legs, where N is not necessarily a natural number.

This thread is 4 years old now, by the way.

METHODS FOR PUTTING AN ELEPHANT INTO A REFRIGERATOR:

Algebra: Show that parts of the elephant can be put into the fridge, then show that the fridge is closed under addition.

Number Theory: Use induction, you can always squeeze a bit more in.

Analysis: Differentiate the elephant, put it inside the fridge, then integrate.

Topology: The elephant is compact, so it can be put into a finite collection of refrigerators. That's usually good enough.

Algebraic topology: Replace the interior of the refrigerator by its universal cover, R^3.

Set theory: refrigerator = { elephant }

Numerical analysis: Put its trunk in and refer the rest to the error term.

Mark44
Mentor
I have always loved "obvious to the most casual observer" to mean "I have no idea how to derive this"!

There is the old story of the professor who said "No, it is obvious that", hesitated, said "Now why is that obvious?", sat down at his desk, scribbled furiously for 20 minutes, then jumped up and said "Yes, it is obvious!"
"Obvious to the most casual observer" was always a favorite of mine as well. An instructor I had at a small community college used that one frequently. Another he used a lot was "Even my own mother could integrate that!" When he was about to do something tricky, he would say "Watch closely! At no time will the chalk leave my hand or will my hand leave my arm."

jasonRF
Gold Member
"Obvious to the most casual observer" was always a favorite of mine as well. An instructor I had at a small community college used that one frequently. Another he used a lot was "Even my own mother could integrate that!" When he was about to do something tricky, he would say "Watch closely! At no time will the chalk leave my hand or will my hand leave my arm."
I think we all had profs that did these things! For 2nd semester intro physics (EM+special relativity), the professor would always say things like, "from grade-school calculus we know ...". I recall the TA asking the prof in lecture "how did you go from the top equation to the second equation?" Answer: "I just integrated by parts 3 times in my head", as if it should have been obvious.

For the final, one of the problems began, "if photons have a mass, the wave equation becomes ..." followed by an equation with a bunch of dels floating around. I remember it well because I walked out of the exam stunned, just shaking my head.

I think profs get a kick out of this sort of thing.

jason

A mathematician, a physicist and an astronomer are riding a train across the Scotish countryside.

The astronomer looks out the window and sees a sheep in the field. He points and says, "Look in Scotland sheep are black!"

The physicist sighs and says, "Now, now. In Scotland, at least one sheep is black."

The mathematician loses it! "Will you two ever learn? In Scotland there exists a field. In that field there exists a sheep. One side of which is black!"

That's actually my all time favorite joke out of all jokes.

hermann weyl used to say that a compact city can be guarded by a finite number of arbitrarily-nearsighted policemen

Mark44
Mentor
I saw this one in a different section, and thought it deserved to be here as well. Credit goes to Cronxeh.

Six engineers and six mathematicians are attending a conference and are traveling by train. One by one, each of the engineers goes up to the ticket counter and buys a ticket to the conference. But only one of the mathematicians does. The engineers look puzzled and one of the mathematicians says, "Optimization."

The twelve get on the same car and one mathematician stands at each end of the car. Now the engineers are really puzzled. After a while, the mathematician at one end, yells, "Conductor!" On that cue, all the mathematicians pile into the rest room and lock the door.

The conductor enters the car and announces, "Tickets, please. Tickets!" He passes the engineers and punches each of their tickets. At the end of the car, he notices the restroom is occupied and knocks on the door, "Ticket, please."

The ticket slides out from under the door, he punches it and slides it back, then leaves the car and continues to the next car.

The engineers look at each other and decide how clever the mathematicians have been, and then wink at each other.

They all attend the conference and have a good time. Upon arriving at the train station, one engineer buys a ticket and they giggle at each other. The mathematicians do not buy any. This time again, the engineers look puzzled, and the same mathematician says, "Optimization."

This time all the mathematicians sit down and the engineers have the lookouts. One engineer, peers down a couple of cars and shouts, "Conductor!" Immediately all the engineers pile into the rest room, while the mathematicians just sit there. Once the engineers are in the rest room, one of the mathematicians knocks on the door and says, "Ticket, please." The ticket slides out under the door, the mathematician grabs it and along with the other mathematicians, runs to the other rest room and they lock themselves in.

This one is from my High School Days. π is pie

QTπ RU/18

Our physics lecturer used to say "...according to what I have already erased..."
We had a lecturer who was reputed to be able to make a term disappear by writing it fainter each line.

A bunch of Polish scientists decided to flee their repressive
government by hijacking an airliner and forcing the pilot to fly them
to a western country. They drove to the airport, forced their way on
board a large passenger jet, and found there was no pilot on board.
Terrified, they listened as the sirens got louder. Finally, one of
the scientists suggested that since he was an experimentalist, he
would try to fly the aircraft.

He sat down at the controls and tried to figure them out. The sirens
got louder and louder. Armed men surrounded the jet. The would be

The experimentalist calmly replied, "Have patience. I'm just a simple
pole in a complex plane."
Perhaps it's just from too much time learning about the Riemann Hypothesis recently, but this one killed me.

Already saw my favorites posted: What's purple and commutes? An abelian grape.
I'm sorry, the number you have dialed is imaginary, please multiply by i and try again.

153 and 641 were dating, and 153 said to 641, "I love you 641. I love how you're a sum of fourth powers. I love how you're a divisor of a Fermat number."

641 replied, "I, uh, I love you too, 153."

"Why do you love me, 641?" asked 153.

"Well, I uh, I love how you're the sum of the cubes of your digits."

"You don't love me!" cried 153. "You just like my base ten representation!"

Old but good:

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A mathematician walks into $$\overline{A}$$ and says "I'm sorry, I didn't realize you were closed".

METHODS FOR PUTTING AN ELEPHANT INTO A REFRIGERATOR:

Algebra: Show that parts of the elephant can be put into the fridge, then show that the fridge is closed under addition.

Number Theory: Use induction, you can always squeeze a bit more in.

Analysis: Differentiate the elephant, put it inside the fridge, then integrate.

Topology: The elephant is compact, so it can be put into a finite collection of refrigerators. That's usually good enough.

Algebraic topology: Replace the interior of the refrigerator by its universal cover, R^3.

Set theory: refrigerator = { elephant }

Numerical analysis: Put its trunk in and refer the rest to the error term.
Analysis:
1) Differentiate it and put into the refrig. Then integrate it in the refrig.
2) Redefine the measure on the referigerator (or the elephant).
3) Apply the Banach-Tarski theorem.

Number theory:
1) First factorize, second multiply.
2) Use induction. You can always squeeze a bit more in.

Algebra:
1) Step 1. Show that the parts of it can be put into the refrig.
Step 2. Show that the refrig. is closed under the addition.
2) Take the appropriate universal refrigerator and get a surjection from refrigerator to elephant.

Topology:
1) Have it swallow the refrig. and turn inside out.
2) Make a refrig. with the Klein bottle.
3) The elephant is homeomorphic to a smaller elephant.
4) The elephant is compact, so it can be put into a finite collection of refrigerators. That's usually good enough.
5) The property of being inside the referigerator is hereditary. So, take the elephant's mother, cremate it, and show that the ashes fit inside the refrigerator.
6) For those who object to method 3 because it's cruel to animals. Put the elephant's BABY in the refrigerator.

Algebraic topology:
Replace the interior of the refrigerator by its universal cover, R^3.

Linear algebra:
1) Put just its basis and span it in the refrig.
2) Show that 1% of the elephant will fit inside the refrigerator. By linearity, x% will fit for any x.

Affine geometry:
There is an affine transformation putting the elephant into the refrigerator.

Set theory:
1) It's very easy!
refrigerator = { elephant }
2) The elephant and the interior of the refrigerator both have cardinality c.

Geometry:
Declare the following:
Axiom 1. An elephant can be put into a refrigerator.

Complex analysis:
Put the refrig. at the origin and the elephant outside the unit circle. Then get the image under the inversion.

Numerical analysis:
1) Put just its trunk and refer the rest to the error term.
2) Work it out using the Pentium.

Statistics:
1) bright statistician.
Put its tail as a sample and say "Done."

2) dull statistician.
Repeat the experiment pushing the elephant to the refrig.

3) Our NEW study shows that you CAN'T put the elephant in the refrigerator.

^lol

$$\int e^x = e^x + C$$

i know its missing the dx, its supposed to read sex = extc

sorry, i know its lame..

Borek
Mentor
We have separate thread for lame jokes.

These are supposedly questions actually asked of applicants for a programming job:

How do you put a giraffe into the refrigerator?

Correct answer: Open the refrigerator door, put the giraffe in, and close the door. This question tests whether or not the candidate is doing simple things in a complicated way.

How do you put an elephant in the refrigerator?

Incorrect answer: Open the refrigerator door, put in the elephant, and close the door. Correct answer: Open the refrigerator door, take out the giraffe, put in the elephant, and close the door. This question tests your foresight.

The Lion King is hosting an animal conference. All the animals in the world attend except one. Which animal does not attend?

Correct answer: The elephant. The elephant is in the refrigerator, remember? This tests if you are capable of comprehensive thinking.

There is a river notoriously known for it’s large crocodile population. With ease, how do you safely cross it?

Correct answer: Simply swim across. All of the crocodiles are attending the Lion King’s animal conference. This questions your reasoning ability.

Mark44
Mentor
^lol

$$\int e^x = e^x + C$$

i know its missing the dx, its supposed to read sex = extc

sorry, i know its lame..
I learned it as

$$\int e^x = f(u^n)$$

I like my version because it's an actual formula.

Borek
Mentor
Without dx it is not.

ok smart guy it can still be read like a real integral: integral of e to the x equals e to the x + c.

or Sex=ex t C