Full set of all possible special relativity symmetries:
- translations in space and time
- rotations in space
- Lorentz boosts
In simple and concrete terms. Suppose you observe N particles following different trajectories in Spacetime.
There are two observers traveling at constant speed relative to each other, and so they see different trajectories for those particles:Note that the first two types of transformation are exactly the non-relativistic Galilean transformations.
- space and time shifts, because their space origin and time origin (time they consider 0, i.e. when they started their timers) are not synchronized. This can be modelled with a 4-vector addition.
- their space axes are rotated relative to one another. This can be modelled with a 4x4 matrix multiplication.
- and they are moving relative to each other, which leads to the usual spacetime interactions of special relativity. Also modelled with a 4x4 matrix multiplication.
The Poincare group is the set of all matrices such that such a relationship like this exists between two frames of reference.
When you fail a HR interview, then you know you've reached rock bottom.
Investments:
- 2024: 75m GBP
- 2023-04: 15m GBP: www.uktech.news/deep-tech/riverlane-series-b-20230424 At 100 employeed on LinkedIn, this should keep them going for two more years.
- 2022 500k GBP: www.uktech.news/deep-tech/riverlane-rigetti-quantum-innovate-uk-20220628 by Innovate UK for joing project with Rigetti Computing to work on quantum error correction
The Operating System for Quantum Computing by Steve Brierley (2021)
Source. Founding CEO. He seems nice. You might as well just start watching at: youtu.be/ugzWnw1LTBE?t=1166 where more specific things start to come out.Was adopted by AskJeeves in 2001.
The Google Story Chapter 11. "The Google Economy" comments:
As they saw it, generation one was AltaVista, generation two was Google, and generation three was Teoma, or what Ask Jeeves came to refer to as Expert Rank. Teoma's technology involved mathematical formulas and calculations that went beyond Google's PageRank system, which was based on popularity. In fact, the concept had been cited in the original Stanford University paper written by Sergey Brin and Larry Page as one of the methods that could be used to rank indexed Web sites in response to search requests. "They called their method global popularity and they called this method local popularity, meaning you look more granularly at the Web and see who the authoritative sources are," Lanzone said. He said Brin an Page had concluded that local popularity would be exceedingly difficult to execute well, because either it would require too much processing power to do it in real time or it would take too long.
googlesystem.blogspot.com/2006/03/expertrank-authoritative-search.html mentionsand:
ExpertRank is an evolution of IBM's CLEVER project, a search engine that never made it to public.
The difference between PageRank and ExpertRank is that for ExpertRank the quality of the page is important and that quality is not absolute, but it's relative to a subject.
There are other more recent algorithms with similar names, and are prehaps related:
- www.researchgate.net/publication/257015904_ExpertRank_A_topic-aware_expert_finding_algorithm_for_online_knowledge_communities ExpertRank: A topic-aware expert finding algorithm for online knowledge communities (2013)
- ieeexplore.ieee.org/document/5260966 ExpertRank: An Expert User Ranking Algorithm in Online Communities
Besides being useful in engineering, it was very important historically from a "development of mathematics point of view", e.g. it was the initial motivation for the Fourier series.
Some interesting properties:
- TODO confirm: for a fixed boundary condition that does not depend on time, the solutions always approaches one specific equilibrium function.This is in contrast notably with the wave equation, which can oscillate forever.
- TODO: for a given point, can the temperature go down and then up, or is it always monotonic with time?
- information propagates instantly to infinitely far. Again in contrast to the wave equation, where information propagates at wave speed.
Sample numerical solutions:
This is one of the main reasons why Ciro Santilli invested in OurBigBook.com.
Ciro believes that the only thing students must be forced to learn is to speak read and write English and that a teacher's main job after that is to help students find their next big goals and also ties into the backward design philosophy.
Everything else, the student must choose.
This idea is generally known as self-directed learning.
This is most notable in University entry examinations of poor countries, where students often have to waste one extra year of their lives to go through preparation for the useless university entry exams. And then, surprise surprise, if they actually get in, they find that this is not what they really wanted to do, and they just go through to the end miserably because they understandably they don't want to risk another year of their lives.
And importantly: It must be easy to change your area of study.
Ciro saw this first hand École Polytechnique which was way freer than his university in Brazil.
Steve Jobs's university dropout stories from Steve Jobs' 2005 Stanford Commencement Address also come to mind.
Interesting projects:
- Brown University's Open Curriculum concept sounds exemplary:
- Gallatin School of Individualized Study from New York University
- Advanced Placement
The Purpose of Education by Noam Chomsky (2012)
Source. - 0:00 discusses education as a system of indoctrination: indoctrination for people to comply with the Establishment and pass tests, vs the Age of Enlightenment in which education should help you achieve your own intellectual/life goals. He suggests without specific evidence that after the 60's there was explicit intervention in the US to increase the indoctrination aspect, of which debt is a part.
- 15.45: assessment vs autonomy: exams are useless, except as a tool to help improve teaching and self assess. Tells anecdote about little girl who wanted to learn more about a subject, asked teacher how to learn more, teacher said you can't, you have to study for this useless national exam instead which will determine your future, and if I'm rehired or not.
Godfrey Hounsfield, 1979 Nobel Prize in Physiology and Medicine:[ref]
They tried hard to educate me but I responded only to physics and mathematics
Related ideas:
Before we get a decent open source integrated development environment, what else can you do?
But also perfect for small one-off files when you don't have the patience to setup said IDE.
vim's defaults are atrocious for the 21st century! Vundle is reasonable as an ad-hoc package manager, but it can't set fixed versions of packages:
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