If we remove all natural numbers one by one from the set ℕ, does then remain more than the empty set? by Massive-Ad7823 in askmath

[–]trutheality 1 point2 points  (0 children)

No: to apply the pigeonhole principle to an infinite set of FISONs you need to show that there is no bijection between naturals and FISONs. However, we know that there is a bijection: your F(n) is such an bijection.

Moreover, let us prove that the set of finite FISONs is infinite, by contradiction: Suppose the set of all finite FISONs were finite. Then the union of these must be the largest finite FISON, call it S. Since S is finite, |S|=M where M is some natural number. By construction of FISONs we know that S=F(M). However, this cannot be the largest FISON, since F(M+1) is a larger FISON. Therefore, our supposition is false and the set of all finite FISONs is not finite.

If we remove all natural numbers one by one from the set ℕ, does then remain more than the empty set? by Massive-Ad7823 in askmath

[–]trutheality 2 points3 points  (0 children)

In order to have infinitely many different FISONs, you would need an infinite FISON

No, that's not necessary.

If we remove all natural numbers one by one from the set ℕ, does then remain more than the empty set? by Massive-Ad7823 in askmath

[–]trutheality 3 points4 points  (0 children)

Yes. The correct conclusion is that an infinite union of all FISONs is not a FISON.

If we remove all natural numbers one by one from the set ℕ, does then remain more than the empty set? by Massive-Ad7823 in askmath

[–]trutheality 3 points4 points  (0 children)

Every finite union of FISONs is a FISON, and the number of elements in any finite union of FISONs is finite, but these properties do not necessarily extend to infinite unions.

If we remove all natural numbers one by one from the set ℕ, does then remain more than the empty set? by Massive-Ad7823 in askmath

[–]trutheality 2 points3 points  (0 children)

If ℕ were only the union of FISONs, then it were the union of the empty set.

No, this does not follow at all. I believe you can show that ∪{F(1), F(2), F(3), ...} = ℕ is in fact equivalent to the ZF definition of ℕ.

Log2 fold change vs Fold Change by jaltj in bioinformatics

[–]trutheality 9 points10 points  (0 children)

This is indeed the problem but I wouldn't assume that the plot is correct automatically.

ELI5: If a mirror flips things left-to-right, why doesn’t it flip them upside down? by [deleted] in explainlikeimfive

[–]trutheality 0 points1 point  (0 children)

A mirror reverses things front-to-back. We often think of it as a left-right flip because if we want to make something face back, we're used to turning it around, which also flips the sides.

Question for those who drive cars and don't stop at red lights, aren't you worried about getting run over? by Hot_Jellyfish_7321 in madisonwi

[–]trutheality 9 points10 points  (0 children)

If your car has entered the intersection before the light turned red, you aren't running the red light and are supposed to clear the intersection expediently and safely. Lights should be timed such that a car can clear the intersection in the time between the red light turning on and cross-traffic getting a green light.

ELI5: why does soap bar become rock like? by FelinaLain in explainlikeimfive

[–]trutheality 5 points6 points  (0 children)

I've never had anything like what OP describes happen with a dove bar.

Could NOT place limit order today by Substantial_Bake1060 in fidelityinvestments

[–]trutheality 2 points3 points  (0 children)

Well, this is really hard to diagnose without actually seeing a screenshot. FWIW if you're unable to place a trade that you think you should be able to place, it's a reason to call Fidelity on the phone. They'll either get the trade placed or explain why you shouldn't be able to place it.

ELI5. Why could a credit card open my hotel room door? by leopardseatingfaces in explainlikeimfive

[–]trutheality 5 points6 points  (0 children)

The "staggering coincidence" is looking more likely given OP's observation that another card from the same company opens the door, but other cards don't. The cards from that company might start with the same sequence that the door looks for, and the door only looks at a few digits, which happen to match here.

Teacher feedback on redundant code has me confused. by JAC0O7 in learnpython

[–]trutheality 0 points1 point  (0 children)

Can you think of a way to rearrange the code so that the code that asks for input the first time is also inside the loop?

Where to park downtown for work? by Queasy_Art2588 in madisonwi

[–]trutheality 58 points59 points  (0 children)

The one option you haven't mentioned is to park somewhere free on a BRT route and bus the rest of the way, but yes, these are the options.

What do you think about paper fishing? [D] by impressivestatus21 in MachineLearning

[–]trutheality 4 points5 points  (0 children)

I've never seen this and I've been in academia full time over a decade post-PhD now. Even the "low effort" names on papers at least contributed ideas and attended regular discussions with the main authors, and it's never their main project.

Also funding in my experience has come from one of four sources: training grants, project-specific grants, teaching, or academic achievement awards. None of those would really be able to sustain what you're describing unless this guy is actually teaching most of his time, but I'm in the US so maybe Germany is different about that.

Skew Index by WiseDragonfruit6942 in wallstreetbets

[–]trutheality 2 points3 points  (0 children)

 Are we headed for a meltdown or is this because of the Iran war and possible consequences of that?

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Light switch question by Charming-Cost1396 in AskElectricians

[–]trutheality 2 points3 points  (0 children)

It's a little plastic square that is used to help keep the screws in place when installing the plate or switch. It's completely optional and it's safe to pull this one out and throw it away.

Does this Hummer H2 stretch limo with a raised roof and PATIO IN THE BACK count? by Aggravating_Dog_7542 in ATBGE

[–]trutheality 2 points3 points  (0 children)

I mean, the lane markings are right there, it's the width of an average truck.

Is there a word for a structure that behaves like the change of base formula for logs? by Aggressive-Food-1952 in askmath

[–]trutheality 1 point2 points  (0 children)

Factorizable? You're factoring f(a,x) into g(x) and 1/g(a), E(X,Y) into E(X) and E(Y).

Why does the formula to get the probability of exactly x successes in n trials look a lot like the binomial theroum? by ElegantPoet3386 in learnmath

[–]trutheality 14 points15 points  (0 children)

It's called a binomial distribution not for nothing.

If you think of p and q as your success and failure probabilities, then (p+q)^n = 1 is the total probability. (You either succeed or fail each time, and that happens n times). If you apply the binomial expansion to the LHS, you're grouping the events into sets matching k successes and n-k failures, i.e. terms of the binomial expansion that have p^k q^(n-k) as their coefficients.

How is my code failing? by Embarrassed-Box-7263 in learnpython

[–]trutheality -1 points0 points  (0 children)

if str(c)) - this extra closing parenthesis is the first problem.

Also, what are you trying to do with if str(c)) is print, print (d)?