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/sci/ - Science & Math

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10328434 No.10328434 [Reply] [Original]

>sit in on signal processing course to see how much of a joke engineering courses are
>professor says Dirac Delta "function"

>> No.10328441

What's wrong? It's a function from the space of functions to the reals

>> No.10328493

>>10328434
>Dirac Delta "function"
Paul Dirac called it a function, and that should be good enough for you, retard.

>> No.10328529

>>10328434
>professor says Dirac Delta "function-al"

the al is silent, you brainlet. He actually pronounced it correctly

>> No.10328566

>>10328434
Haven't seen this thread for a while, though
>distributions aren't functions
The terms generalized function was a mistake.

>> No.10328608

>>10328434
exactly why everyone hates mathematicians. i always make a POINT of calling it a function to trigger math idiots

>> No.10328619
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10328619

>>10328608
>math people are the idiots for following the actual rules
>youre not an idiot if you just hope you get the right answer

>> No.10328622
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10328622

>>10328608
>exactly why everyone hates mathematicians. i always make a POINT of calling it a function to trigger math idiots

>> No.10328626

>>10328619
>math people are so fucking autistic and ignorant, they don't understand that heurestic, intuitive or general-non rigorous rules are used because the point of certain courses is to apply math to real world problems
In my functional analysis class, it was so fucking sweet to see all the mathfags get completely destroyed by any exercise that was applied in some way. Distribution theory has plenty of diminishing return if you just want to study pde's and their solutions.

>> No.10328633

>>10328626

engineers dont take functional analysis with mathematicians

>> No.10328634
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10328634

>>10328619
>>10328622
assume N is even
by Goldbach's theorem, N is a sum of two primes

>> No.10328637

>>10328633
Well, then it means I broke some law. Double Majors are a thing. Almost everyone agrees that from the hard STEM, math is the easiest major.

>> No.10328671

>>10328434
New idea
[eqn]\begin{array}{cccl} \delta_a: & \mathscr P\left(\mathbf R\right) & \longrightarrow & \left\{0,\;1\right\} \\ & A & \longmapsto & \mathbf 1_A\left(a\right) \end{array}[/eqn]
[eqn]\int_I f\left(x\right)\, \delta\left(x\,-\,a\right)\, \mathrm dx \quad\longrightarrow\quad \int_I f\,\mathrm d\delta_a[/eqn]
Hopefully, mathfags will start to understanding that I'm the smartest person who's ever lived.

t. engineering student.

>> No.10328673

>>10328671
That's called the dirac measure, it's not really new, but if you know 0 measure theory, that would be pretty cool.

>> No.10328766

>>10328673
Exactly, and a measure is a function. Mathfags will be baffled at how incredibly fucking smart I am.

>> No.10328794

>>10328434
I'm surprised you've kept this meme going on for so long, not that I really disagree with your contention.

>> No.10328808

>>10328434
My prof says the same thing. Enlighten a third year aero eng fag what pure math lords call the Dirac Delta.

>> No.10328821

>the virigin pure mathematician
everything needs to be rigorous, has no intuition
only does exact calculations, doesnt know when to ignore irrelevant aspects
never achieves anything useful

>> No.10328822

>>10328766
A measure is a function into the extended nonnegative reals.
You can't call dirac delta a function into the extended reals because it's meant to be convolved with things, which makes no sense for two functions with different targets.

>> No.10328824

>>10328808
It's a functional. Specifically, the evaluation at zero functional.

>> No.10328826

>>10328434
https://en.wikipedia.org/wiki/Spede_Pasanen

>> No.10328828

>>10328821
What a sad, moronic post.
Engisneers are really SEETHing on /sci/ these days.
We respect ourselves enough not to bother with imperfect systems.

>> No.10328857

>>10328822
The extended reals contain the reals, so a function doesn't need to be infinite at any point to be a measure. The absolute state of mathfaggs. https://en.wikipedia.org/wiki/Dirac_measure

>> No.10328931

>>10328857
Yes, but how do you multiply in the extended reals?
I'm actually not sure how measure theory deals with this (say, with product measures). I forget.
And of course a function doesn't need to be infinite at any point to be a measure. That's not what I'm saying. But a measure is a function from a collection of sets to the extended reals, and neither dirac delta nor any function you'd convolve it with has as its domain a sigma ring.
What are you on about?

>> No.10328934

>>10328857
By the way, I >>10328931 know what a Dirac measure is, and sure it's a way of formalizing what you want. But it's not the common way. The common way is to just call it the kernel of the evaluation at zero functional.
Why do you have such a chip on your shoulder about this?

>> No.10328946

>>10328931
>>10328934
Ah, no that there is no function [math]\delta :\mathbb{R}\to\mathbb{R}[/math] that chas the properties of the dirac delta. This means, the integral over the dirac measure cannot be "represented" by lebesgue integration with some real valued function. And it doesn't work if you define it as "infity" at 0, because the measure of the set where it isn't 0 is, well 0. The point that >>10328671
was making was that you could call the dirac delta function the dirac measure which is a function. Also, you can define product in the extended reals perfectly fine.

>> No.10329997

>>10328434
Based Dirac Delta "function" poster.
Haven't seen this thread in a while.

>> No.10330707

>>10328634
1+2 = 3

>> No.10330835
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10330835

>>10328434
Sounds like a shit-tier signal processing class, desu

>> No.10331554

Any mapping from one set to another is a function.

>> No.10333240
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10333240

bump

>> No.10334672

>>10330707
>1+2 = 3
not true. what you probably mean is that there is a homomorphism called 'evaluation' from the set of arithmetic formulae over whatever number set into some other properly chosen set of numbers, and that this homomorphism maps 1+2 and 3 to the same number.

>> No.10334687
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10334687

>>10328622

>> No.10334705

>>10328671
I am the smartest programmer to ever live.
t. Terry Davis

>> No.10334760

>>10328619
Always follow never lead
The life of the virgin mathematician

>> No.10334770

>>10328626
I think most mathfags shudder at the thought of their subject actually being used in the real world instead just being an academic circle jerk.

>> No.10336731

>>10334760
>doing stupid shit thats literally fucking wrong is "leading"
keep coping retard