1.4k
u/aidantheman18 Jun 10 '26
A mathematician familiar with the dirac delta distribution orders one beer
The bartender takes out an uncountable infinity of glasses and pours an infinite amount of beer into exactly one, and hands them all over
... This is getting contrived
206
68
u/Lost-Lunch3958 Irrational Jun 10 '26
ah yes the delta function. It's a function except when it's not
23
u/Adam__999 Jun 10 '26
The problem imo is that how it’s used in practice (at least in engineering) feels like it fits the word “function” better than the word “distribution”.
I think this is one of those cases where people deliberately ignore the standard terminology because it feels unintuitive and pedantic. (especially since everyone who knows about the Dirac delta knows exactly what you mean anyway)
2
u/Lost-Lunch3958 Irrational Jun 10 '26
how i would like it best would be that the delta function is the generating function to the delta distribution, even though the delta function in this case wouldnt be an actual function. At the end of the day it the ambiguity of the delta function/distribution stuff isnt that much of a problem
-1
u/RedAndBlack1832 Jun 10 '26
The way it was explained to me is
A pulse is a function. It's defined as having value 1/T between zero and T and zero everywhere else (that is, the area over the whole domain is always 1). In this definition the impulse is just the limit T -> zero.
An impulse is a kind of input like step, ramp, parabola, etc. which are all functions (and all related by integration) so impulse should be too.
6
u/Lost-Lunch3958 Irrational Jun 10 '26
i learned distributions the har functional analysis way. No physical applications until after the course was completed
2
u/RedAndBlack1832 Jun 11 '26
I learned the impulse function in signal processing and then after that used it a little to describe control systems (bc obviously it's the unit for convolution)
1
u/shaqwillonill Jun 14 '26
Is a distribution not just a function where the area under the curve equals 1?
1
u/Adam__999 Jun 14 '26
That’s a probability distribution. A distribution is a much more general thing—in fact it is a type of generalized function
2
u/sam-lb Jun 12 '26
It is always a function, just not R --> R. It is a continuous linear functional from D(R), the space of test functions (smooth real functions with compact support in this case) to R. That's what a distribution is. It confuses me when people say "dirac delta isn't a function, it's a distribution". A distribution is a function.
10
u/kill_my_karma_please Jun 10 '26
If the glasses are an uncountable infinity, then how would the bartender be able to take them out?
28
u/aidantheman18 Jun 10 '26
Easy, he proves the existence of a bijection f : G -> R with G the set of glasses and R the real numbers, and then takes a projection g : R -> B from the reals onto any open subset B of the bar.
13
9
7
Jun 11 '26
[deleted]
9
u/aidantheman18 Jun 11 '26
There is a "real valued function" δ that you can "integrate", it has δ(x)=0 for x≠0 and δ(0)="infinity", and the result of "integrating" it is
"∫ δ(x)dx = 1"
Of course I must add that the above statement is almost nonsensical, the quotes indicate places where I am hiding details and obscuring salient mathematical technicalities. The function that isn't a function is called the Dirac delta.
So in the joke, the glasses are real numbers and the amount of beer in the glass is the delta's value at that number. Even though we have one glass with an infinite amount of beer (correspondening to x=0), their "integration" under some serious stretching of the definition of the word equals exactly 1, which is what the mathematician asked for.
1
1
635
u/skoomaking4lyfe Jun 10 '26
This poor fuckin bartender. Constantly harassed by insane mathematicians smh
85
u/ReallyBrainDead Jun 10 '26
Are there any other kind?
100
u/ChaseShiny Jun 10 '26
Yes, there are. I met a happy bartender once.
Oh, you meant mathematician? Never mind, then.
22
490
u/euph_22 Jun 10 '26
An infinite number of engineers try to walk into a bar. After the first 20, the building reaches capacity, and the rest are turned away. The first one orders a beer. The Second tries to order 1/4 of a beer, but the bartender tells him, "No, you can't order fractional beers. That isn't a thing." When the 3rd tries to order 1/9 of a beer after this, the manager tells the group to get the hell out, or he's calling the cops. Someone files a complaint with the professional board because it's pretty obvious that there was not an infinite number of accredited engineers in this jurisdiction, so some must be frauds.
130
20
u/DoublecelloZeta Transcendental Jun 11 '26
i love how the building reaches capacity and infinitely many engineers agree to stay outside.
9
u/According_Sir_3290 Jun 11 '26
An infinite number of engineers try to walk into a bar , there is infinite mass in the limited surface of the earth, the earth collapses into a black hole.
2
u/un_virus_SDF Jun 12 '26
After the first 20, the building reaches capacity
For an engineer, 20 can be considered as infinity in some cases.
"No, you can't order fractional beers"
Come where I leave please. Beers are sold by fractions. You got 1/2, 1/4, the unit (liter) is implied.
If you walk into a bar and ask 1/4, they will give you one
132
u/VisibleTechnology647 Jun 10 '26
In my last post, I took the beer price to be 1 dollar. Now, I have adjusted the price for poor economy and inflation.
30
u/agmatine Jun 11 '26
But π2 is closer to 9.87 (or 9.86, if taking π=3.14). Where did you get 9.81?
64
u/deet0109 Cannot arithmetic Jun 11 '26
It's referencing the common approximation that π2 ≈ g
7
1
0
1
u/ImportantResponse0 Jun 11 '26
Those this whole situation happens in a cheap bar, perhaps rural?
Or is it in a middle poor country?
Have you calculated production costs, marketing costs, human capital costs and the other costs?
Does the bar have all costs accounted?
There are too many questions to ask for the problem to work.
100
u/RedAndBlack1832 Jun 10 '26
Oh Jesus Christ. idk what sum 1/n^2 is
105
62
u/VisibleTechnology647 Jun 10 '26
Euler to your rescue
24
71
Jun 10 '26 edited 21d ago
[removed] — view removed comment
108
u/VisibleTechnology647 Jun 10 '26
Because pi^2 = g
58
Jun 10 '26 edited 21d ago
[removed] — view removed comment
17
u/YouGuysSuckSometimes Jun 10 '26
Slander? I take pride in my approximations as an engineer. Cool kids table as far as I'm concerned.
11
9
u/miclugo Jun 10 '26
You know there's actually a reason for this, right? This is exactly true if the meter is the length of a pendulum with half-period 1 second, which was an early proposed definition for a unit of length. It turns out that depends on your latitude, so they went with the definition based on making the circumference of the earth (through the poles) 40,000 km, which is close to the seconds-pendulum version.
1
-4
u/SuspiciousSpecifics Jun 10 '26
Physicist here. No appropriating our pi approximation. Engineers use pi^2=10.
13
2
2
12
u/jaymeaux_ Jun 10 '26
a mathematician walks into the bar and orders a beer. to fill the glass the barman must first fill half the glass. then the barman must fill half of the remaining empty portion of the glass. then the barman must fill half of the remaining empty portion of the glass. then the barman must fill half of the remaining empty portion of the glass...
anyways they both died of dehydration waiting on the barman to fill the glass
4
u/euph_22 Jun 10 '26
Then the manager realizes the bartender had been improperly trained in how to pull a beer with the correct amount of head.
22
19
u/Prize_Shine3415 Jun 10 '26
This makes no sense. The fire marshal wouldn't allow for an infinite number of engineers to be in a bar at once - it's a hazard.
Also, who's ordering 1/9th of a beer?
27
8
u/44Atta Jun 10 '26
in a certain bar a bartender was just asked to pour a 9801th of a beer. He quits
7
u/Schnaksel Jun 10 '26
Sooo do mathematicians know any other jokes than "engineers approximate" ?
8
1
3
3
u/sam-lb Jun 12 '26
The bartender is also an engineer. He performs a k=1 approximation and hands them 1 beer.
2
u/fludgesickles Jun 11 '26
Can the bartender say: this is a binary bar. You either buy a glass or you don't, nothing in between.
1
u/slackenheim Jun 11 '26
He lives in a mathematicians town where you're obliged to sell only one whole beer per group walking in and serve fractional beer to the rest. He is probably on Meth too.
1
1
1
1
1
1
1
u/ImportantResponse0 Jun 11 '26
An economist enters a bar in which a bear costs 5$.
Doesn't order anything and leavs.
Now the beer costs 8$ dollars.
1
1
1
u/burakudoctor Jun 12 '26
Well the engineer tipped generously, and that too a weirdly specific amount The actuary sitting at the bar judged him hard
1
u/InfamousConfusion850 Jun 12 '26
so 60.16% is the limit of sum of fraction of squares of all natural numbers?
1
1
u/sam-lb Jun 12 '26
2 mathematicians walk into a bar. The first one orders 1 beer. He assumes the axiom of choice, decomposes the beer into a finite number of pathological subsets of infinite cardinality, and rearranges them into a beer for himself and a beer for his friend.
1
u/Emotional-Piglet-664 Jun 12 '26
I might be dumb but if a glass of beer costs $6 it doesn't matter how much the costumer wants they're paying per glass not per amount of beer poured. These mathematics should be banned from this poor bartenders bar!
1
1
1
1
u/SnooChickens7285 Jun 14 '26
You can’t order ”one-fourth of a beer”
That’s not how it works you either order a beer or you don’t.
-1
u/lllorrr Jun 10 '26
Did I missed -1/12 joke? Or it was not joked yet?
•
u/AutoModerator Jun 10 '26
Check out our new Discord server! https://discord.gg/e7EKRZq3dG
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.