consilient

14 ms·

91.
by consilient 3y ago
> If you don't come from a math-y background and are trying to "get into serious mathematics", the only way to do this is to get a PhD. > I realize this might come across as gatekeeping, but the reality is that each sub
92.
by consilient 3y ago
> Has anyone ever written a piece of code that's really so difficult for a human to read and figure out whether it halts? Any interpreter for a Turing-complete language is an example.
93.
by consilient 3y ago
> It's possible that what I mean can be turned into a statement like "all functors used in programming are representable", but I'm not sure. No, this is much stronger and definitely false. Any variable-size data str
94.
by consilient 3y ago
> if we can't even use Monads without mathematically knowing they are Monads then no one is ever going to be using them. You don't need to know what a monad is to use one. Everyone who has ever written a computer program has
95.
by consilient 3y ago
> Monads, even when restricted to programming language usage, do not fundamentally have anything to do with continuations. This is a little too strong, I think. If your category is sufficiently nice (complete closed symmetric monoidal, I
96.
by consilient 3y ago
> I agree that it would be interesting to learn what non-strong monads look like. A monad is strong if: - its underlying functor is strong - the strength commutes with the monad unit `return :: a -> m a`, i.e. `return (x,y) === streng
97.
by consilient 3y ago
You need it to be symmetric if you want strength as such instead of left-strength and right-strength, but otherwise yes, it makes sense to talk about strength relative to any monoidal product.
98.
by consilient 3y ago
> What about between the first photons and the first galaxies? ~200-400 million years. There's a lot of uncertainty from early JWST observations that haven't received more detailed measurements yet.
99.
by consilient 3y ago
The CMB is everywhere, but it was emitted by the initial formation of neutral hydrogen (from plasma) in the early universe. When people talk about the CMB being far away they're really talking about the last scattering surface, which i
100.
by consilient 3y ago
> the Planck length is presumed to be the smallest measurable distance before stuff turns into a black hole This is not correct. The Planck length happens to be very very roughly the scale at which we expect effective theories that ign
101.
by consilient 3y ago
> I'm guessing it's the one that says kinetic minus potential energy, but that seems arbitrary It is arbitrary, in some sense: Lagrangians are specifications of a physical system in the same way that laws of motion are. Instead
102.
by consilient 3y ago
No. Some of them are simply wrong. For instance: - action is extremized or at a saddle point, not necessarily minimized - Action is not quantized in QM (and quantum-mechanical action is not quite the same as classical action). There's
103.
by consilient 3y ago
Just skimmed the EM section: I didn't catch anything egregiously wrong , per se (but again, I only skimmed it), but it's mostly fluff, and the actual physics content that does it exist is targeted at wildly different levels. For
104.
by consilient 3y ago
> It's not like the object could move out of the way faster than the speed the light it traveling at (ftl) It doesn't need to move as far as the light does.
105.
by consilient 3y ago
> Shouldn’t physics focus much more on the underlying micro states and micro processes than the emergent phenomena? Obviously there needs to be a transition, but at some point you go from physics to engineering. 1. The boundaries between
106.
by consilient 3y ago
> Magnetic fields fall off with the inverse square law. Inverse cube: the simplest magnets are dipoles. > It's pretty easy to construct a light bulb with a filament which is hotter than the surface of the sun The surface of the s
107.
by consilient 3y ago
> I understand that lambda calculus works with expressions and symbols, while standard function notation works with functions and values There's no inherent connection. You're perfectly free to interpret lambda terms as functio
108.
by consilient 3y ago
> It seems to be some kind of multivariate PCA. No, UMAP is nonlinear. The general idea is that you generate a neighborhood graph of your data points, do a spectral embedding on that to get your initial result, and then do gradient desce
109.
by consilient 3y ago
> How much mass would need to be collided to suck in Earth? A significant fraction of the mass of the Earth. Black holes don't "suck" any harder than other objects of the same mass.
110.
by consilient 3y ago
Room temperature superconductors would not give us zero-cost energy any time soon. Even if one had a high enough critical current to be used in transmission lines (which is not a given), transmission losses are under 10% in modern grids.
111.
by consilient 3y ago
> its great to be excited for real science discoveries but hoaxes are not good, There's absolutely no evidence of a hoax. The original authors were sloppy and overeager, not malicious.
112.
by consilient 3y ago
> They simply aren't particles the way people think of them They're not anything the way laymen think of them. They're not classical particles, they're not classical waves, they're not classical anything. They&
113.
by consilient 3y ago
> Almost every non-trivial component is bound to have some sort of state, doesn't it? No, not at all. Any nontrivial component is going to have some sort of conditional rendering, but whether the inputs are supplied explicitly as fu
114.
by consilient 3y ago
> btw "any other particle" doesn't fall out of EM fields. I very obviously meant that XYZ-particle states fall out of mode expansions of the XYZ-field, not that all particles are EM quanta. > what i said is not backwa
115.
by consilient 3y ago
> The rate of churn is accelerating while nothing really new theory-wise has been added. There's plenty of novel stuff out there, it just takes a long time to filter down to the mainstream. React hooks are probably the best example
116.
by consilient 3y ago
> study some qft I have. Srednicki and Weinberg are sitting on my bookshelf right now. > photons dont exist, dude, except in connection with and at the site of the detector. Exactly backwards. Photons fall out of mode-expanding asympt
117.
by consilient 3y ago
> Stars eventually wind up as black holes. The vast majority of stars will end up as white dwarfs. Stars need to be about 10 times the mass of the sun to undergo core collapse, and about 25 solar masses (or more, depending on composition
118.
by consilient 3y ago
> So from a classical point of view light travels as a wave but interact as a particle. And the classical point of view is wrong . Photons resemble classical particles in a few respects, and classical waves in a few others, but at the e
119.
by consilient 3y ago
A small sample: The existence of `any`; worse yet, the use of `any` in the standard library . Mutable arrays are treated as covariant: the classic `cats : Cat[] ; animals: Animal[] = cats; animals.push(dog);` problem. Methods are both co-
120.
by consilient 3y ago
Turing complete type systems are extremely common. C#, C++, Java - it's hard to avoid if you have subtyping and generics. In practice it almost never comes up.

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