martini.ai | Remote | Worldwide (UTC−05:00) | Full-time | Multiple Roles | $70k - $180k (location-based) + equity
Join martini.ai as we transform the $2 trillion private lending industry. We use cutting-edge AI and deep market insights to provide credit risk estimates for private companies.
We are a small, scrappy team (4 engineers + UX consultants + CTO) with VC funding. The co-founders (CEO and CTO) are repeat entrepreneurs, ex-YC, and ex-Wall Street.
We are looking to bring in people to fill multiple roles.
- Senior Full-Stack Software Developer
- Senior Backend / Devops Engineer
- Senior Machine Learning Engineer
- Quantitative Analyst
We need people who are resourceful, independent and curious, who can thrive in a startup environment. But above all we need people who can be generalists; we are a small team and everybody wears multiple hats. So if you're a dev who is looking to learn a bit about finance, or a quant who is looking to learn a bit more about software, martini.ai is the place for you. Prior experience in finance is a huge plus.
Its extremely implausible, putting it generously, that such fine-tuned structures could even form. They mention at the end "this paper does not attempt to tackle the problem of structure formation" but that feels like a colossal understatement.
I've studied physics myself, and I understand that sometimes people toy around with implausible theories solely for the sake of it but .... it seems like these peoples brainpower could be much better spent elsewhere.
The sense in which they are defects is that on the shell, the density function is a distribution and takes no real value. Distributions are singularities/non-functions that we get when we take certain limits of ordinary functions, or solve certain differential equations with generalized functions.
The distribution used works roughly as if we overlapped two equal positive and negative mass shells. But there are some extra details that ensure there is a net inward force for matter situated on the final shell. We'd have to actually work the math to really understand why that force appears, without hand waving.
I don't disagree with what you've said about distributions, however I don't think that the fact that these shells are created from dirac delta functions is sufficient to call them topological defects.
Topological defects are solutions to the underlying physical equations that are of a different homotopy class to the vacuum, and these simply aren't in a different homotopy class, as I can smoothly deform them to zero, by sending the radius to zero or sending alpha to zero.
Argued another way: a point charge can be modelled as a dirac delta charge distribution, but nobody would argue that a point charge is a topological defect
Okay, fair point, I was not understanding that topological defects are points in solution space that are not path connected to the vacuum solution. I'm learning as I'm going!
Now I also realize that the paper seems to say that the both the ordinary dirac shell solution and their modified shell are TDs, without proving it.
I'd like to work up to proving whether the collapsing modified shell really does homotopy into into a point and then fade away into the vacuum.
But first, I'm struggling with
> nobody would argue that a point charge is a topological defect
It's actually not clear to me that the point mass is not a TD!
Let's try to write the homotopy sending a point mass Mδ₀ to the vacuum solution 0. Let t vary from 0 to 1. Then a possible homotopy is
h(t) = (1-t)Mδ₀
This gives us
h(0) = Mδ₀
h(1) = 0
The problem is that I don't know how to prove continuity of h.
First, I don't know how to compute even the continuity of neighboring Delta functions for t < 1. But that feels intuitively like it should be continuous.
On the other hand, I REALLY don't know how to prove continuity at t = 0, since the function seems to spontaneously collapse from a distribution with a kind of pseudoinfinite value at the origin, into a regular function with the value 0 at the origin.
Using the notation of inner products and test functions, can we prove that it's continuous both for t < 1 and t = 1?
I know that's a bit more technical than we usually get here on HN! I truly appreciate the help!
Okay we are are getting a little lost in definitions here, but nonetheless.
You can solve the above by remembering that the dirac delta is the limit of a series of functions.
If you take your delta to be lim a -> 0 N(0, a) where N() is the normal distribution, then you can see that in your above equation, you then have two limits. lim t -> 0 and lim a -> 0. By swapping the order of the two (which is a dubious operation), you can send t to zero first then a to zero, and the result is zero.
So in one way, it can be deformed to zero, in another way it can't, because it's 0 times infinity .
However, the thing to focus on is that dirac deltas aren't actually valid points in the solution space of partial differential equations. They aren't functions, and they aren't actually physically real.
Come to think of it, that would probably exclude them from being TDs a-priori. Because a TD must be a solution to an underlying physical equation, and that solution must be deformable to zero. But if it's not a solution to a PDE (because it doesn't live in any valid hilbert space), then it can't be a TD.
I think that dirac delta solutions let us model point particles. We can lift differential operators onto the space of D' of distributions. This lets us extend the pde solution set with distributions.
Conceptually this is how we would model a field with interacting particles using PDEs, and is as far as I know the reason we solve with distributions and consider them physical in the first place.
The question of whether dirac is homotopic to vacuum would then mean exhibiting a homotopy in D', which is the dual space to the underlying function space, and represents both functions and distributions as functionals on a space of test functions. The topology of D' is the weak-* topology. Given a net N_t of distributions, N_t converges to N if N_t(g) converges to N(g) for all test functions g.
So to make your proof tight, I propose we should lift it into D', where our family u_t of shrinking deltas is already a net. We'd then prove that u_t -> 0 converges for each test function.
I think the result would be much more satisfying and watertight, since your current proof does not really make up its mind about what it's conclusion is.
Now, I am not sure that the distributions need to be a hilbert spaces to solve PDEs in this sense. This is because distributions have derivatives and can be acted on by our lifted differential operators. These solutions are weak in the sense that they are solutions with respect to the test functions. But I also believe that the solutions are faithful, in the sense that any solution corresponding to a function in the base space will also be a solution for the original operator.
Also, if you need our space of distributions to be a Hilbert space, we can pass to distributions over sobolev n space, the space of functions with square integrable nth derivatives. The distributions here end up being hilbert spaces! Not only that but the square integrability condition is pretty mild and still leaves us a lot of very useful functions for physics. I think that some quantum theories use these kinds of Hilbert spaces. Lol, take that with a grain of salt - this is lore to me, not terra firma.
Anyhow, if you want to try to persuade yourself that we can't just throw away delta functions and other distributions, and then try to lift your proof into space of distributions, I think that would be very fun!
I'll try to do that as well!
Ps. Forgive me if I'm Tom Sawyering you or nerd sniping! Please also forgive me for any mistakes I'm making!
I tried some of the positions in this article while trying to get used to sleeping on the floor in an attempt to fix my back pain. These hurt like hell
I live here as a nomad. Job market is pretty bad. Haven't seen any official statistics but I've heard many locals anecdotally say that the pay even for people with econ / engineering degrees is pretty bad.
Lots of young people with advanced degrees just end up working in call centres, or onlyfans.
I mean sure, but the chances of that ever being enforced are close to 0. I'm a full time digital nomad for over a year in various latin american countries, always on tourist visas. Nobody notices or cares.
The only time I ever had an issue is when entering the united states, the immigration department gave me a grilling because my passport showed that I was clearly a nomad and they expected me to be working online.
The people in the raid got jailed over night as far as I remember. Thailand was basically just noticing this trend and reacting, afaik this hasn't happened again.
About the visas people just were really stupid to be honest about their income (or lack of)
every day we have the chance to observe thousands of thousands of circumcised men and we have been doing this for thousands of men, and so far, nobody has noticed any emotional issues with them.
it's not fallacious, its simply saying that we've (informally) looked at a lot of data and found nothing. I.e. evidence of absence
Morality of the procedure aside, this is a very low quality study.
The most glaring omission is that they didnt account for possible confounding due to religious/political beliefs. To be fair, they acknowledge that this is a limitation, but I'd bet that this is possibly the main driving factor behind any differences in personality between the two groups.
We know for a fact that religious/conservative populations are markedly different across a variety of character traits, and they are also significantly likely to circumcise their child.
Any study that doesnt account for this is invalid IMO.
Religion aside I think a majority of American men and a significant portion of South Korean men are circumcised. These are the two largest populations last I checked. Neither do so for religious reasons but more likely by doctors pushing junk science and peer pressure. The foreskin I believe are sold in many hospitals to pharmaceutical and cosmetic companies, so there is perverse incentive.
I see articles like this a lot and I haven't yet thought of a way to categorize them properly.
I think the author is simply being melodromatic and faulting companies like apple for not designing user interfaces that are perfect.
His concrete complaints against apple boil down to two points really:
* there's a lot of bloatware.
/ too many apps
* the apps/settings menus are hard to navigate.
My day job has me in the trenches right now trying to make good UIs and I can simply say that its hard. Moreover, if you ask the average consumer what they think of apple's UI I bet that most would praise it. If apple, the best company in the world at UI/UX can't make this guy happy, then I'm not sure who will.
His complaints against google have a similar tone. He complains that SEO has slowly eroded the quality of search results, which is true, but also SEO is an adversarial process. Given the value of being at the front page of search, people are strongly incentivised to game the system as hard as they can. It's a hard problem.
Not to be glib, but I'd like to see him try to tackle these problems before saying that big tech is "selling basic usability back to consumers".
Yes, the flaws he points out with usability of big tech products may be real, but I dont think it warrants the venom with which he writes the article.
Even to me, as a tech person, the level of SEO allowed to infiltrate google results seems way out of proportion to what they should allow. There are several obvious URLs that always come up with "top 10 lists" that seem wholly designed for SEO referral links for any type of recommendation you might be looking for. There's a reason everyone just ignores google and adds "reddit.com" to certain searches now to get real results.
Google isn’t, to all outward appearances, trying to do search well, though. I mean, you can want them to deal with SEO better/differently, but it’s clear the goal is to drive advertising and to do whatever it can to serve you more ads. We need more neeva/Kagi search tools, if we want companies incented to get away from blogspam/SEO.
I don't believe that Apple is the best at UI, from by limited experience with them. I have close to zero complaints about Android or Windows UI, besides pull to refresh.
Apple is the best at making tech not feel like it's actually tech, and creating a sense that it's just a transparent window to your content, the way that hand tools are transparent extensions of your hand, rather than interpreters that filter and alter your actions.
People who are already really good at doing stuff in the real world and comfortable in 3D space(The kind who probably gravitated towards skateboards and oil painting instead of video games) feel at home, and don't experience and loss of confidence which would cause them to give up.
It's not really easy to use, they have a ton of gestures and shortcuts. Windows/android is like doing what a screen says, Apple is like learning a dance.
If you have a very active mind that always tries to find patterns of logic, Apple gives you clarity and directness, but it doesn't spell things out and hold your hand as much as some stuff.
> Not to be glib, but I'd like to see him try to tackle these problems before saying that big tech is "selling basic usability back to consumers".
A problem statement is not invalid just because someone pointing it out can't solve it.
The tech industry has incentive ($$$) to improve click rates but very little incentive to improve UI beyond what A/B testing says makes the most money. The author was just claiming that from a consumer point of view.
Maybe so, but I curse it. It hides too much and is opaque and unintuitive. I can never really figure out how to do anything in it without doing a web search to get the answer.
Join martini.ai as we transform the $2 trillion private lending industry. We use cutting-edge AI and deep market insights to provide credit risk estimates for private companies.
We are a small, scrappy team (3 engineers + UX consultants + CTO) with VC funding. The co-founders (CEO and CTO) are repeat entrepreneurs, ex-YC, and ex-Wall Street.
We are looking to bring in people to fill multiple roles.
- Senior Full-Stack Software Developer
- Senior Machine Learning Engineer
- Quantitative Analyst
We need people who are resourceful, independent and curious, who can thrive in a startup environment. But above all we need people who can be generalists; we are a small team and everybody wears multiple hats. So
if you're a dev who is looking to learn a bit about finance, or a quant who is looking to learn a bit more about software, martini.ai is the place for you.
We are a small, scrappy team (4 engineers + UX consultants + CTO) with VC funding. The co-founders (CEO and CTO) are repeat entrepreneurs, ex-YC, and ex-Wall Street.
We are looking to bring in people to fill multiple roles.
- Senior Full-Stack Software Developer
- Senior Backend / Devops Engineer
- Senior Machine Learning Engineer
- Quantitative Analyst
We need people who are resourceful, independent and curious, who can thrive in a startup environment. But above all we need people who can be generalists; we are a small team and everybody wears multiple hats. So if you're a dev who is looking to learn a bit about finance, or a quant who is looking to learn a bit more about software, martini.ai is the place for you. Prior experience in finance is a huge plus.
Tech stack: Python, Pandas, React, Next.js, AWS, Pytorch
Interested applicants should reach out to me, Martin Dupont, at my email: DELETED: Applications are now closed.