Mathematical joke
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A mathematical joke is a form of professional humor which relies on aspects of mathematics or a stereotype of mathematicians to derive humor. The humor may come from a pun or double meaning of a mathematical term, or on a non-mathematician's misunderstanding of a mathematical concept. Such jokes are frequently inaccessible to those without a mathematical bent.
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[edit] Pun-based jokes
An example:
- Why do Mathematicians like national parks?
- Because of the natural logs.
Another example:
- Person 1: What's the integral of 1/cabin?
- Person 2: A log cabin.
- Person 1: No, a houseboat - you forgot to add the c!
The first part of this joke relies on the fact that the primitive (formed when finding the antiderivative) of the function 1/x is log(x). The second part is then based on the fact that the antiderivative is actually a class of functions, requiring the inclusion of a constant of integration, usually denoted as C - something which many calculus students forget. Thus, the indefinite integral of 1/cabin is "log(cabin) + c", or "A log cabin plus the sea", ie. "A houseboat".
Yet another example is:
- Q: What do you get if you cross an elephant with a chicken?
- A: Chickens Elephants sin(θ)
This relies on the formula for the "cross product" of two vectors X and Y being equal to Y times X multipled by the sine of the angle between them (theta).
A follow up to the above joke is:
- Q: What do you get if you cross an elephant with a mountain climber?
- A: You can't, the mountain climber's a scaler.
This is a similar cross product joke, with the added pun on the word "scalar" (i.e. not a vector) vs. "scaler" (i.e. one who climbs).
Some of these jokes rely on the fact that many mathematical terms have non-mathematical meanings, such as the one-liner:
- A topological set can be open or closed, but some are neither. Are these sets "ajar"?
[edit] 'Mathematical pun'-based jokes
- There are only 10 types of people in the world -- those who understand binary, and those who don't.
This joke relies on the fact that mathematical expressions, just as expressions in natural languages, may have multiple meanings. When multiple meanings are available, puns are possible. In this case a pun is made using the expression 10. For non-mathematicians or non-computer programmers 10 almost always refers to the number ten. However, in binary, the expression 10 means the number two. Thus the joke says that there are only two kinds of people, those who understand binary, and those who don't. However, those who do not understand binary will certainly not get the joke. It must be noted this joke is only feasible in written form; when speaking a binary number aloud, most would phrase "10" as "One Zero" rather than "Ten".
A self deprecating version is as follows:
- There are only 10 types of people in the world -- those who understand binary, and those who get laid.
A similar joke may be played by asking the question:
- If only DEAD people understand hexadecimal, how many people understand hexadecimal?
In this case, DEAD refers to a hexadecimal number (57005), not the state of being no longer alive.
Another pun using different radices, sometimes attributed to computer scientists, asks:
Another joke involving counting is:
- There are three kinds of people in the world: those that can count, and those that can't.
This implies, of course, that the person making the statement is the second kind.
Almost everyone knows the trite line: "Why did the chicken cross the road?" "To get to the other side". A mathematical variation follows as: "Why did the chicken cross the Möbius strip?" This joke relies on the audience knowing that since the Möbius Strip is a surface with only one "side" (i.e. one "edge"), anyone trying to give the typical answer will realise its impossibility. The answer is sometimes also given as "To get to the same side", with the same rationale.
- I love f(x)ou.
This pun is based on that fact that the function f(x) is the same as the letter y in terms of graphical equations. The possibilities for other puns similar to this are many, though the above is the simplest to understand.
[edit] Mathematical reasoning
A similar set of equivocal jokes applies mathematical reasoning to situations where it is not entirely valid. Many of these are based on a combination of well-known quotes and basic logical constructs such as syllogisms:
Examples:
- Premise I: Power corrupts.
Premise II: Knowledge is power.
Conclusion: Therefore, knowledge corrupts.
- Premise I: God is love.
Premise II: Love is blind.
Premise III: Stevie Wonder is blind.
Conclusion: Therefore, Stevie Wonder is God.
- Premise I: Imitation is the sincerest form of flattery.
Premise II: Imitation is suicide. (Ralph Waldo Emerson)
Conclusion: Therefore, suicide is the sincerest form of flattery.
The second and third of these syllogisms happen to be logical fallacies even when taken in a purely logical sense.
There are also a number of joke proofs, such as the proof that "Girls are evil":
- Girls require time and money: <math>girls = time \cdot money\,</math>
- "Time is money": <math>time = money\,</math>
- So girls are money squared: <math>girls = money^2\,</math>
- "Money is the root of all evil": <math>money = \sqrt{evil}</math>
- So girls are evil: <math>girls = \left (\sqrt{evil} \right )^2 = evil</math>
Some might think that the square root of a number squared is equal to its absolute value (actually, in the above formula it is the square of the number's root, so this assumption is false), thus girls are actually equal to <math>\left | evil \right |</math>. Given that evil is considered a negative quality, one may argue that this proof only exemplifies that girls are in fact, good, so the argument goes. Alternatively, to say that girls are equal to the absolute value of evil may infer that they are absolutely evil. In fact, this case is the square of a square root and not the square root of a square. The <math>\sqrt{-evil}</math>, i.e. a negative evil, would actually be <math>i\sqrt{evil}</math>, which squared would still be <math>-evil</math>. Positive or negative evil, rooted and squared, is still positive or negative respectively.
Another set of jokes relate to the absence of mathematical reasoning, or misinterpretation of conventional notation:
Examples:
- <math>\Big( \lim_{x\to 8} \frac{1}{x-8} = \infty \Big) \implies \Big( \lim_{x\to 3} \frac{1}{x-3} = \omega \Big)</math>
- <math>\frac{\sin{x}}{n} = \frac{\mbox{si}\, x}{1} = 6</math>
[edit] Mathematicians
Some jokes are based on stereotypes of mathematicians tending to think in complicated, abstract terms, causing them to lose touch with the "real world".
Many of these jokes compare mathematicians to other professions, typically physicists, engineers, or the "soft" sciences in a form similar to those which begin "An Englishman, a Scotsman and an Irishman ..." or the like. The joke generally shows the other scientist doing something practical, while the mathematician does something less useful such as making the necessary calculation but not performing the implied action.
Examples:
- A mathematician and his best friend, an engineer, attend a public lecture on geometry in thirteen-dimensional space. "How did you like it?" the mathematician wants to know after the talk. "My head's spinning", the engineer confesses. "How can you develop any intuition for thirteen-dimensional space?" "Well, it's not even difficult. All I do is visualize the situation in n-dimensional space and then set n = 13."
- A mathematician, a biologist and a physicist are sitting in a street café watching people going in and coming out of the house on the other side of the street. First they see two people going into the house. Time passes. After a while they notice three persons coming out of the house. The physicist says, "The measurement wasn't accurate." The biologist says, "They must have reproduced." The mathematician says, "If one more person enters the house then it will be empty."
- A sociologist, a physicist and a mathematician are each locked in a prison cell and given a supply of canned food, but no can opener. After thirty days, the cells are unlocked. The sociologist's cell has dents in the walls, and smashed cans and food everywhere. He threw the cans at the walls randomly until they burst open, and salvaged enough food to survive. The physicist's cell wall is covered in calculations, and one corner is heavily damaged. He calculated the optimum way to throw the can at the wall to make it burst open reliably (within a reasonable margin of error), and he too survived. The mathematician's cell wall is likewise covered in calculations, but there are no dents in the walls. In fact, inside the cell sit the pile of cans, unopened, and the corpse of the mathematician. He was able to derive a nonconstructive proof that showed there was a way to throw the can of food at the wall, but could not find the solution.
- A mathematician and an engineer agreed to take part in a psychological test. They sat on one side of a room and waited not knowing what to expect. A door opened on the other side and a naked woman came in the room and stood on the far side. They were then instructed that everytime they heard a beep they could move half the remaining distance to the woman. They heard a beep and the engineer jumped up and moved halfway across the room while the mathematician continued to sit, looking disgusted and bored. When the mathematician didn't move after the second beep he was asked why. "Because I know I will never reach the woman". The engineer was asked why he chose to move and replied, "Because I know that very soon I will be close enough for all practical purposes!" (The joke hints at the dichotomy paradox)
- The relationship between pure and applied mathematics is based on trust and understanding: the pure mathematicians don't trust the applied mathematicians, and the applied mathematicians don't understand the pure mathematicians.
Mathematicians are also averse to making sweeping generalisations from a small amount of data, preferring instead to state only that which can be logically deduced from the given information - even if some form of generalisation seems plausible:
- A mathematician, a physicist, and an engineer were traveling through Scotland when they saw a black sheep through the window of the train. "Aha," says the engineer, "I see that Scottish sheep are black."
- "Hmm," says the physicist, "you mean that at least one Scottish sheep is black."
- "No," says the mathematician, "all we know is that there is at least one sheep in Scotland, at least one side of which looks black from here!"
A variant has the punchline "No," says the mathematician, "all we can say is that there is at least half of a black sheep in Scotland."
Pure mathematicians are mainly concerned with the properties of the abstract systems under study, not their actual applications. However, such applications are sometimes found in mathematics itself, resulting in new insights as old problems are cast in new light. In striving not to miss such connections, mathematicians often see problems in novel (but theoretically valid) ways, which unfortunately are not always as illuminating as one could wish for:
- A sociologist, a physicist and a mathematician are all given equal amounts of fencing, and are asked to enclose the greatest area. The sociologist pauses for a moment and decides to enclose a square area with his fence. The physicist, realizing he can fence off a greater amount of land with the same amount of fencing, promptly sets his fence in the form of a circle, and smiles. "I'd like to see you beat that!" he says to the mathematician. The mathematician, in response, takes a very small piece of his own fencing, and wraps it around himself, proclaiming, "I define myself to be outside of the fence!"
A small set of jokes involves only mathematicians, such as the following involving statisticians:
- Three statisticians go duck hunting. Their dog chases out a duck and it starts to fly. The first statistician aims and takes his shot, it misses a foot too high. The second statisticians aims and takes his shot, it misses a foot too low. The third statistician says, "We got him!"
The humor there is derived from the fact that the average of the shots hits the duck, and so it is dead. Another such joke is:
- What does a mathematician do when he gets constipated?
- He grabs a pencil and works it out.
Here the humor exists in two aspects. In one aspect the joke pokes fun of the tendency of mathematicians to use their intellect in situations where it isn't needed. The joke also presents an ambiguity whereby it can be interpreted as a mathematician trying an even more misguided solution.
Another type of joke is of historical mathematicians. For instance,
- Why did the chicken cross the road?
- Pierre de Fermat: Because the margin on this side was too small.
[edit] Non-mathematicians
The next category of jokes comprises those that exploit common misunderstandings of mathematics, or the expectation that most people have only a basic mathematical education, if any.
Examples:
- A visitor to the Royal Tyrell Museum was admiring a Tyrannosaurus fossil, and asked a nearby museum employee how old it was.
- "That skeleton's sixty-five million and three years, two months and eighteen days old," the employee replied.
- "How can you know it that well?"
- "Well, when I started working here, I asked a scientist the exact same question, and he said it was sixty-five million years old - and that was three years, two months and eighteen days ago."
In the above example, the humour is that the employee fails to understand the precision of the age of the fossil. (However, this is not strictly a joke about mathematics, but instead about science/engineering.)
- Two mathematicians are in a bar. The first one says to the second that the average person knows very little about basic math. The second one disagrees, and claims that most people can cope with a reasonable amount of math. The first mathematician goes off to the washroom, and in his absence the second calls over the waitress. He tells her that in a few minutes, after his friend has returned, he will call her over and ask her a question; all she has to do is answer, "One third x cubed." She agrees, and goes off mumbling to herself. The first guy returns and the second proposes a bet to prove his point. He says he will ask the blonde waitress an integral, and the first laughingly agrees. The second man calls over the waitress and asks, "What is the integral of x squared?" The waitress says, "One third x cubed." Then, while walking away, she turns back and says, "Plus a constant!"
In the above example, the humour is that the waitress, chosen as an example of someone not expected to know much mathematics beyond adding up the bill, turns out to know enough calculus to correct the mathematician's omission.
[edit] Non-mathematical mathematical jokes
One final form of mathematical humor comes from using mathematical tools (both abstract symbols and physical objects such as calculators) to form words and phrases, often of a crude nature. These constructions are generally devoid of any "real" mathematics, besides some basic arithmetic. One such example is calculator spelling, words and phrases formed by entering a number and turning the calculator upside down. Due to their crudeness and relative simplicity (requiring only basic calculator skills to achieve), they are usually spread by schoolchildren. Often the words are accompanied by stories involving numbers that lead to the "final solution".
Example:
- <math>b_4i\sqrt{u}\frac{ru}{18}</math>
This can be read, interpreting the expression mathematically, as "Before I root you, are you over 18?" (in Australian and New Zealand English, "to root" is slang for "to have sex with", from the verb "rut", meaning animal mating).
Example: A t-shirt from the University of Chicago reads: <math>\lim_{U \to U(C)} \int e^x = 0</math>
or: The limit of sex (the integral looks like an "S") as U (you) approaches U of C is zero, implying that the average U of C student is unlikely to engage in sexual relations.
Example:
- A hillbilly asks his son what he learned in school that day. The son responds, "Pi R squared" (<math> \pi r^2\!</math>). The angry father comes back with, "What are they teachin' you in that place? Everybody knows cornbread are squared; pie are round!"
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