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throwawaymath

5,982 karma · joined April 20, 2018

I've left. This used to be an enjoyable place to debate, but now it's frustrating to see ideologically driven downvotes on valid and on-topic comments.

I no longer have access to this account. If you want to reach me for past comments, you can do so at throwawaymathhn@gmail.com.

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throwawaymath··on Modern SAT solvers: fast, neat and underused
Gurobi, CPLEX and XPRESS are the obvious commercial ones. GLPK and Cbc will also do MILP.

For more information, see this page: http://plato.asu.edu/guide.html

throwawaymath··on Sam Altman’s leap of faith
> think about the hacking capabilities of AGI for a moment

We're discussing the hypothetical skills and capabilities of a thing which is fundamentally science fiction. The rules are treated as arbitrary.

I don't see a priori why an AGI would be intrinsically good at hacking, or even why it would be capable of exponentially improving itself.

This is the problem I see with any discussion of AGI. The game's rules don't matter, so we can define whichever properties we'd like for the sake of argument. There's no skin in the game to counteract that, because we have no conception of what AGI will actually be like - nor if it's even possible.

As it stands, in your comment and the rest of this thread I see a variety of leaps and jumps to scenarios which seem completely undefended.

throwawaymath··on Sam Altman’s leap of faith
I'm skeptical of OpenAI, but to be charitable I don't think economic value is the primary goal for their AGI. Their position seems to be that it needs to be one of several necessary goals in order to repay investors for helping them scale up to achieve it in the first place.
throwawaymath··on Chicago successfully taxes streaming services
18 is quite close to 10, in an absolute sense. The context of that citation is a claim that it's statistically inaccurate to say police officers risk their lives. That claim is demonstrably not borne out by statistics. Out of the universe of available professional work, being a police officer is #18 in risk. It's a rather small consolation that they're not eight jobs higher up the chain in terms of risk, considering there is essentially no chance of e.g. my monitor killing me as I sit at my desk.

A valid takeaway from the cited list is that being a police officer isn't literally the most dangerous thing you can do for work. An invalid takeaway is that being a police officer isn't dangerous.

throwawaymath··on Chicago successfully taxes streaming services
Statistically speaking, yes, if your compensation model pays commensurate with risk. But I'm not sure I see how that's relevant to the discussion at hand.

You started by saying that the claim that police officers risk their lives is statistically inaccurate, with a citation. I countered that citation with one of my own and a calculation showing they do risk their lives. Now you are talking about garbage collectors and their exposure to risk being greater than that of police officers.

That doesn't really counter my point about police officers' lives being exposed to risk, because I never made a claim that police officers are exposed to more risk than garbage collectors. Likewise I'm not forwarding a normative point about whether or not people should be paid commensurate with the amount of risk they encounter in their professional work. I am making the narrow, positive point which is that, objectively speaking, police officers are exposed to risk (and this is borne out by statistics).

I'm not in a position to make a normative claim about whether or not (or how much, in an absolute sense) we should compensate people more for risking their lives. I'm not sure if you were expecting me to say that garbage collectors shouldn't be paid more than police officers in hazard pay. But if we are assuming a system that pays commensurate with risk, then I'm happy to agree it would be internally consistent to pay garbage collectors more than police officers in hazard pay, sure.

throwawaymath··on Chicago successfully taxes streaming services
It strikes me as a bit disingenuous to say it's not even in the top 10 when it's number 18, according to that list. At that point we're talking about a difference of degree, not category. If anything your citation supports the idea that police officers endanger their lives.
throwawaymath··on Chicago successfully taxes streaming services
Okay, but it is listed in the top 20. What you're citing doesn't seem to support your thesis; in fact, it appears to refute it. With that in mind, and considering the foregoing back of the napkin math I presented, I'm still not following how police officers don't endanger their lives.
throwawaymath··on Chicago successfully taxes streaming services
Why do you consider the idea that police officers risk their lives to be statistically inaccurate? According to the United States Department of Justice, there are approximately 1,100,000 police officers in the entire country[1]. If 144 police officers died last year, a given police officer has (assuming uniformity) slightly greater than a 0.01% chance of dying each year. In other words one out of every 10,000 officers is killed.

Assuming surviving one year does not impact the likelihood of dying the next year, over a 20 year career a police officer then has a 0.26% chance of dying in the line of duty. We can expect that slightly greater than two out of every 1,000 officers will die prior to retirement.

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1. https://www.bjs.gov/content/pub/pdf/nsleed.pdf

throwawaymath··on SAT to Add ‘Adversity Score’ That Rates Students’ Hardships
I hate to be that person, but could you maybe cite those statistics? I was willing to give a pass on 95% of churches being 95% racially homogeneous, but I'm deeply skeptical the 85% figure is true for all millennials.
throwawaymath··on SAT to Add ‘Adversity Score’ That Rates Students’ Hardships
That is incorrect. The Jewish people comprise an ethnoreligious group: https://en.m.wikipedia.org/wiki/Ethnoreligious_group

In fact, the term "Jewish people" refers principally to an ethnic group with a common cultural heritage and ancestral religion, not to adherents of Judaism. Judaism happens to be the common religion of the Jewish people.

throwawaymath··on Facebook has struggled to hire talent since the Cambridge Analytica scandal
Mark Zuckerberg does not say he doesn't care about anyone's privacy in the article you cited "openly and repeatedly" or otherwise. I suppose you can infer that from the actions of the company he runs, but your citation does not support what you've said here. Someone reading your comment without reading the entire Guardian article could come away with an incorrect impression of what he's publicly said.
throwawaymath··on GopenPGP, an open source encryption library for native applications
I’m not sure I understand why Protonmail forked the Go crypto library here. Did they fork the entire thing and make substantial changes/updates throughout, or did they just make changes to the PGP implementation available in Go/crypto?

Go/crypto already implements elliptic curve cryptography[1], so I’m curious which specific elliptic curve primitives (or algorithms) they added to their fork.

________

1. https://golang.org/pkg/crypto/

throwawaymath··on The Curse of Genius
Is your alternative hypothesis that ADHD is twice as prevalent in people who feel they have "something to prove"?
throwawaymath··on The Subtle Art of the Mathematical Conjecture
Yes, exactly. And more importantly, resolving mathematical conjectures is more about developing new theories than it is answering singular questions. We don't just care about the Riemann hypothesis because of its utility in solving problems related to the first n numbers; we care about Riemann because of how its implications can be used to solve problems concerning number systems in the abstract.

It only seems strange to continue doubting a conjecture like Riemann if your perspective on the subject is experimental. In the scheme of things the relative impact of Riemann on the first trillion cases isn't nearly as important as what it says about all numbers.

throwawaymath··on Ask HN: Where can I do a self-study math degree online?
The University of Illinois at Urbana-Champaign offers a wide variety of mathematics courses online for self-paced study[1]. The courses range from 100 - 400 level. 100 - 300 level courses confer undergraduate course credit at UIUC, whereas 400 level courses are eligible for graduate credit. (Note that you are not enrolled as a degree-seeking student in a mathematics program, you're simply taking courses online).

You have 16 weeks from the date of registration to complete each course. The courses themselves have weekly homework, two midterms and a final. You must find an eligible proctor to complete the midterms and final in person, but otherwise you need not go anywhere. Each course costs about $1500 - 2000. The lectures for each unit are video recordings of lectures in the corresponding course onsite at UIUC. There is also a certificate you can earn, but it's primarily focused on completion of lower-level courses.[2] Your homeworks are graded (with feedback) by a lecturer or math TA at the university. There are also remote office hours available.

UIUC is probably the highest caliber mathematics program which offers something like this. It's generally difficult to find a top ~20 math university willing to support online, self-paced study for credit. The ones which do offer such a system are usually very expensive[3] or predominantly focus on lower-level courses like a simple calculus sequence.

_____________________________

1. https://netmath.illinois.edu

2. https://netmath.illinois.edu/academics/certificate-program

3. https://cvn.columbia.edu/program/columbia-university-applied...

throwawaymath··on America just had its lowest number of births in 32 years, report finds
Clever, but incorrect. This is a rhetorical construction which falls apart if you don't overload the word, "reduce."

Climate change is bad because it can end human lives. The lives which it doesn't end may experience significant hardship and unhappiness.

Decreasing the rate of population growth does reduce the number of existing humans, but it doesn't induce that reduction by ending lives. It also doesn't increase the amount of hardship imposed on most humans.

Do you see why climate change and population reduction are not comparable?

throwawaymath··on Going Critical
Is the SIR model a Markov model? The article doesn't mention whether or not infection can be modeled as a Markov process, but based on the graphics it looks like it.

If I understand correctly the probabilistic infection rate is "history-less"; in other words, the probability of infecting an adjacent neighbor in the current state is not determined by the state transitions of any previous iterations.

It looks like you could model this naively with a discrete time Markov chain using a 3x3 stochastic matrix and three states: healthy, infected and deceased. I would guess you could do the same thing for the SIS model using states susceptible and infected with a 2x2 stochastic matrix instead.

In either case, modeling the epidemic as a Markov process would let you estimate the probabilities of criticality using the limit of the stochastic matrix. In fact, I think the critical threshold (probability of the epidemic going critical) will be given by left multiplying the initial probability vector by the limit of the stochastic Markov matrix.

throwawaymath··on Calculus with Julia
In my opinion a more all-encompassing (if also more obtuse) definition would be: Calculus is the study of completeness.

I rather like this phrasing because basically everything you'll learn in calculus is a consequence of the completeness property of the reals.

throwawaymath··on A Note on SIMON-32/64 Security
Nice, I forgot that one. BearSSL is one of only two TLS implementations (if I recall correctly) that wasn't vulnerable to the most recent Bleichenbacher attack variant.
throwawaymath··on Books and lectures don't work
It's interesting how the author compares and contrasts learning from books and learning from lectures. I don't entirely disagree, but I think there's an implicit caveat here: these methods are often used inefficiently. They may be intrinsically inefficient, but I think there might be diminishing returns to designing an entirely new medium instead of encouraging a few comparatively simple - but significant - improvements to how we use what we have.

I'll use math as an example since it's what I'm most familiar with. Sheldon Axler, the author of Linear Algebra Done Right, recently released a new textbook on measure theory and integration[1]. He makes the following comment in his preface to the student:

> If you zip through a page in less than an hour, you are probably going too fast.

I loved reading that because it's true, but also because most authors of math textbooks don't spell that out for students. I don't think Guns, Germs and Steel should take an hour per page, but my point is that nonfiction material should be actively engaged with, rather than passively "absorbed." When you passively read a chapter of a math textbook you'll almost certainly fail the exercises. On the other hand if you actively read the material, attempt proofs before reading the author's, investigate how many and which definitions can be removed before a proof fails, come up with your own questions, etc. then you will master the material.

I don't know how you'd do that for a non-technical nonfiction domain, but at it's core I suspect it would dramatically improve the efficiency of learning from books. Likewise, I consider it bad technique to take notes during a lecture. If your professor is implicitly encouraging this by making it so that you have no choice but to do so in order to learn the material (i.e. some material is not in the book or easily found elsewhere, or there is idiosyncratic style), then I also consider that poor form. In my opinion you can significantly improve the efficiency of lectures as a transmission medium by having students lightly read through the relevant sections before the lecture, then actively listen with their entire attention while sitting the lecture.

I also think it would be worthwhile to have lectures recorded and uploaded for a course so students can review material without needing to rely on the book. If you combine these two mediums in the way I've suggested, I really think there is not a whole lot of improvement left to do. There might be a fundamentally novel and strictly superior way of learning, but it's hard for me to see which cognitive bases aren't covered by combining these two methods.

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1. http://measure.axler.net/MIRA10May2019.pdf

throwawaymath··on A Note on SIMON-32/64 Security
Thanks for posting this, I came here to post the same thread.

For those who are unaware: Thomas Pornin is a professional cryptographer. He's a member of the NCC Crypto Services team and one of the authors of the Sosemanuk stream cipher, which was part of the final portfolio for eSTREAM. He's also involved in the development of one of the cryptosystems which has made it to round 2 of the ongoing NIST PQCRYPTO standardization process.

His writing on crypto.stackexchange is prolific and highly informative, and this is a strong rebuttal in particular.

throwawaymath··on A Note on SIMON-32/64 Security
The context Bernstein is talking about is very meaningful here. The mathematics of public-key cryptography provides a rich tapestry for covering up hidden backdoors. ARX ciphers are very simple compared to elliptic curves, and the complexity of round constants isn't really comparable to that of curves.
throwawaymath··on A Note on SIMON-32/64 Security
> which implies the NSA is incompetent at maths

No, it doesn't.

EDIT: To whoever downvoted - developing cryptography is hard. The idea that developing one broken cipher implies mathematical incompetence is laughable. You can't draw any conclusion from it except that it's hard to develop ciphers which aren't broken.

throwawaymath··on The Beauty of Calculus [video]
I don't think it's worthwhile to engage in applied versus pure "math war" either, but I don't really agree with the point you've made. All applied mathematics has an axiomatic basis. When certain mathematical theories can be "applied" to real world problems, it simply means the relevant axioms and definitions are a robust approximation of reality.

To speak to your example directly: machine learning absolutely has an axiomatic basis. You can conduct legitimate research in implementations and software or hardware optimizations thereof; however, fundamentally every experimental result in machine learning is an application of a variety of theorems in linear algebra, probability theory or calculus.

throwawaymath··on The Beauty of Calculus [video]
Putting aside the common issues with pedagogy, the reason you learn a "bunch of tricks" for calculus is because that's more or less all you have in many cases.

If you take integration as an example, there is no single approach to solving every integral. More importantly, it's extremely common to encounter integrals for which there exists no closed form antiderivative. In fact it's technically exceptional to find an integral which can be neatly solved in the space of all possible integrals.

As a direct result, solving an integral becomes an (often frustrating) exercise in transforming it into something equivalent integrals up to a negligible constant. Nonlinear optimization problems and differential equations are similar in this regard.

There is something to be said for the depth of analysis, which does provide a deeper meaning and rigor to the "bag of tricks" in calculus. Outside the US it's somewhat common to skip calculus entirely and begin straight away with analysis, and I think there's merit to that. But the profundity and power of analysis doesn't provide you with any fundamentally more complete methods of solving calculus problems except insofar as they become more advanced and rigorous. Ultimately analytic mathematical work (as opposed to algebraic) is characterized by this kind of pattern-matching; this frequently results in seemingly inspired, bizarre looking proofs compared to how neat everything is in algebra.

throwawaymath··on Google AdWords Exploit Seen in the Wild
My understanding is that's not the purpose of the obfuscation. The parties doing this don't generally want to hack users or compromise accounts, they want people to go to their site instead of the more recognizable one.

If they start actively phishing users this way they're solidly in illegal hacking territory on a pretty massive scale. What they're currently doing is "only" a "growth hack" to get more people on their site instead of the competitor's site.

throwawaymath··on Google AdWords Exploit Seen in the Wild
I think you're speaking to a point the parent wasn't really making. All they're saying is that being known as the canonical source for a brand gives you a steep discount on bidding for that brand name.

We can quibble about the philosophical role of modern search engines I guess, but the basic idea is just that it should be easy to defensively bid on your own thing.

throwawaymath··on The Access Economy: Why the Normal Distribution Is Vanishing (2015)
> Similarly, there's not really a market for software that doesn't work.

Not sure you and I are in the same market, friend.

Engineers and doctors are highly commoditized compared to professional athletes and celebrity entertainers. We produce a fundamentally fungible good.

If you can pay the market rate, you can find a replacement engineer to work your software. If Taylor Swift's concert is sold out, you cannot see Taylor Swift. If Aaron Rodgers dies, there are how many quarterbacks in the world capable of replacing him?

These are categorically different things with categorically different market dynamics. Approximately no software engineers (or doctors) have a personal brand, nor an objectively superior skillset.

throwawaymath··on Self Studying the MIT Applied Math Curriculum
Technically speaking, no. Real analysis is pretty self-contained. You basically start out by constructing the reals from scratch and deducing continuity as a consequence of the completeness of the real field. You use a tiny bit of set theory to establish notation and define bounds, and then from there you go into limits, derivatives, integrals and maybe the Lebesgue measure. I wouldn't expect a real analysis course targeted at applied math majors to do much other than that.

The reason real analysis is useful is because it's (loosely) a deeper calculus course with proofs. Since probability theory becomes more proof-based (and ventures into measures), real analysis is good preparation for it.

throwawaymath··on Self Studying the MIT Applied Math Curriculum
Golub's Matrix Computations is definitely a gold standard, but I wouldn't characterize it as something you read so much as reference :)
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