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joigus

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Everything posted by joigus

  1. No general rule in non-linear equations. This system is particularly simple because it's a 'scrambled' set of quadratic equations in x and y. You can un-scramble it easily, find the conditions for K, and overlap.
  2. I am. For starters
  3. How significant is the Arizona flip?
  4. I don't know what the status of the question is, but this is exactly the part I didn't understand at all. It seems like Tina is reconsidering and I on my part think everybody is being considerate and trying to understand the problem. Not at all, @wtf. I think you understand it better than anybody else here. At least than me. I applaud your suggestion to start with simpler numbers.
  5. I wouldn't be too surprised if there were something to those claims. During the Cold War there were similar episodes in science. Thank you.
  6. 1 is not a prime and those are not the first 23 primes. Don't trust me with numbers. The first 9 primes, I should have said. Thank you @studiot.
  7. I was a bit surprised that such a simple formula would hold for a problem like this. Prime numbers are quite unpredictable. Prime gaps for example cannot be predicted by a general formula. So a formula giving all possible sum decompositions of products of primes... I didn't see the flaw in the argument, because I didn't see the argument. But again, number theory is not within my comfort zone.
  8. I see what you mean. But I think we basically agree about that: So the decomposition of 223'092'870 into a pair of numbers x+y with x, y, not necessarily being prime, but being relative primes of 2, 3, 5, ..., 23, I think is the defining condition. I'm way past my comfort zone here. Fortunately @Sensei did it for all of us, and even though I'm not a great code reader, I think it's what the OP was asking.
  9. You guys are very valuable members of this community. I've been swept away by both of you several times. Yes, you're right, @studiot. But the OP was about the very special, very non-prime number \( 2\cdot3\cdot5\cdot7\cdot11\cdot13\cdot17\cdot19\cdot23 \), factor of the first 9 prime numbers.
  10. Why wouldn't rational and irrational numbers be summable?
  11. Sorry, the problem reduces to how many numbers there are between 1 and 223'092'869 that are not divided by 1, 2, 3, 5, ..., 23.
  12. Now that I think about it, the product of the first 23 is, as you say, 223092870. Now, the number of ways in which you can sum two (arbitrary) natural numbers to give N is just 111'546'435, because 223'092'870 is even. So the problem reduces to finding how many numbers there are between 1 and 111'546'435 that are not divided by 1, 2, 3, 5, ..., 23 (the 1st 23 primes). The only thing I can say is that's not an elementary problem. How did you get your conjecture @Tinacity? Counterexample: \( \pi \) is irrational; \( 1-\pi \) is irrational too. but \( \pi + 1- \pi = 1 \).
  13. She didn't specify, but I thought it was kind of implied... For arbitrary products of primes, certainly nothing like that can be proved with the present mathematics. But for 223092870, I just don't know.
  14. The maths for predicting that kind of thing is called number theory. I know very little about number theory. It studies connections between numbers. The result that you propose reminds me of some theorems by Fermat. Have you proved it, or is it just an intuition? Maybe @wtf or @Sensei, or @mathematic, or @taeto can help you. @studiot is encyclopedic. Maybe he can help you too. Number theory is not very interesting for physics, AFAIK. And physics and mathematical physics are my turf.
  15. joigus replied to studiot's topic in The Sandbox
    It's a mark-up language; a subset of XML: https://www.w3.org/Math/whatIsMathML.html Sorry what I posted was inline LateX, but you can read it as MathML by right-clicking.
  16. This could be hard proof of tunneling for macroscopic objects...
  17. Thank you, Zapatos. I've found a little bit more of the geological history on Wikipedia: https://en.wikipedia.org/wiki/Kegon_Falls From https://www.visitnikko.jp/en/spots/kegon-falls/ The place is such a tourist magnet that it's kinda difficult to find something more science-oriented about it: Geology, fauna and flora, etc.
  18. Another real-estate agency's hopes have been shattered, as we speak.
  19. joigus replied to DrmDoc's topic in The Lounge
    I always thought they were laughing.
  20. NASA has found water on the Moon's lit surface. https://www.npr.org/2020/10/26/927869069/water-on-the-moon-nasa-confirms-water-molecules-on-our-neighbors-sunny-surface?t=1603753199805 https://www.nature.com/articles/s41550-020-01222-x#_blank Abstract from Nature Astronomy: Interesting news, though not Earth-shattering, probably.
  21. joigus replied to studiot's topic in The Sandbox
    Testing some inline maths like \( d^{3n}xd^{3n}p\rho\left(x,p\right) \), \( y = x^2 \) or \( \varepsilon_{\alpha\beta\gamma}\varepsilon_{\alpha\mu\nu}=\delta_{\beta\mu}\delta_{\gamma\nu}-\delta_{\beta\nu}\delta_{\gamma\mu} \) should work.
  22. Mating-brilliant. (@ Koti.)
  23. LOL. A noose, that's what it is. <giggle>
  24. I was thrown away from that discussion with the escape velocity.
  25. joigus replied to mundane's topic in Organic Chemistry
    IOW, why are acids so important, so central to chemistry? They say the basic unit of chemical exchange is the electron. But that's only half the story. Protons are very powerful mediators of chemical reactions too. And the reason is that the size of a hydrogen atom compared to the size of just a proton (ionized hydrogen) is like the size of the Earth compared to the size of an orange. So when you have a substance that is capable of liberating protons, you're liberating myriads of little "positive versions of the electron," so to speak. That's why there is no central concept in chemistry of how easily a substance can liberate any other ion, like e.g. Na+. But liberating H+ is very powerful, very reactive. Protons are elementary particles, small as can be, and move about very freely, especially in aqueous solution. The mitochondria in your cells are powerful proton-pumps.

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