Posted by E-Reverance 2 days ago
Eg. the integral of x^10 is x^11 / 11 + c. No hyper-operation appears and it's just another exponential (with a division).
The integral of log(x) is xlog(x) - x + c. So still basically just a logarithm
Even the integral of 2^x is just 2^x / log(2). Still basically the same thing.
There's no easy way to pull a hyper-operation out.
However a lot of DEs in physics are linear second-order with coefficients that are most often constants or polynomials, and if they're not polynomial they are made to be so using series expansions, under reasonable assumptions. This already brings you a long way towards solving the problem. The resulting equations usually have trigonometric/exponential/special function solutions.
It's still possible that hyper-operations like a double exponential might come up in the study of some specific non-linear problems. As in the example above, if you have an exponential function as a coefficient in your differential equation you might get a double exponential in the solution somewhere. I'm not familiar with any specific physics examples though.
Logarithms are laughably simple once you've fully internalized the meaning of the log function; it simply answers the question:
"To what power must I raise the base to get the argument?"
This is why the output tapers out as you increase the argument; because even if you increase the argument exponentially, you only need a fixed increment in the power to reach that number... So if you increase the argument only by a fixed amount (linearly) instead of exponentially, then it makes sense that the output will grow sub-linearly.
I remember when I was doing algebra with logs many years ago at school, I was applying rules to remove the log from one side of the equation.
Then when I got to uni, I had to revise the rules but it was kind of silly of me because those rules can be trivially derived if you just think about what the log function means. Turns out I had been solving equations with logs throughout school without understanding what they even meant... It's only at university that I actually bothered to learn them.
Actually TBH. I didn't even fully understand powers for some time even though I was doing calculus with them at school. I only fully understood powers once I properly internalized the concept of k-ary trees as a proxy.
It's one thing to be able to apply something, another to understand it. And I think to innovate with something, as a tool, it's not enough to be able to apply it. You must understand it.
Seeing there is nothing (right well-beloved Students of the Mathematics) that is so troublesome to mathematical practice, nor that doth more molest and hinder calculators, than the multiplications, divisions, square and cubical extractions of great numbers, which besides the tedious expense of time are for the most part subject to many slippery errors, I began therefore to consider in my mind by what certain and ready art I might remove those hindrances. And having thought upon many things to this purpose, I found at length some excellent brief rules to be treated of (perhaps) hereafter. But amongst all, none more profitable than this which together with the hard and tedious multiplications, divisions, and extractions of roots, doth also cast away from the work itself even the very numbers themselves that are to be multiplied, divided and resolved into roots, and putteth other numbers in their place which perform as much as they can do, only by addition and subtraction, division by two or division by three.
This is what provides the intuition viz; convert multiplication/division/etc. of large numbers into addition/subtraction of two other smaller numbers. Logarithms as inverse of Exponentiation came much later. Starting with this generally confuses the student since they do not understand the point of it all.
From https://en.wikipedia.org/wiki/History_of_logarithms;
Napier conceived the logarithm as the relationship between two particles moving along a line, one at constant speed and the other at a speed proportional to its distance from a fixed endpoint.
Since the speed is directly proportional to its remaining distance from the fixed endpoint, it therefore is a deceleration, which results in the characteristic "flattening" of the curve.
Further details for understanding the above can be found at Priority, Parallel Discovery, and Pre-eminence: Napier, Burgi and the Early History of the Logarithm Relation (pdf) - http://www.numdam.org/item/RHM_2012__18_2_223_0.pdf
The idea of exponential growth and the practice of charging interest in finance are both ancient. Surely an ancient mathematician would have investigated these in depth and discovered what Napier, Bernoulli and others found?
A while ago I was solving several infinite series of exponentials in the context of a problem concerning the half-life of medicines and I made frequent use of logarithms. That is when I started to wonder about their history.
Here is an interesting book; The History of Mathematical Tables: from Sumer to Spreadsheets - https://en.wikipedia.org/wiki/The_History_of_Mathematical_Ta...
We have lost a lot of knowledge accumulated and written down on biodegradable material (eg. papyri/palm leaves etc.) before the advent of the printing press made knowledge dissemination cheaper and easier. We then compounded the problem by dismissing everything before the beginning of our "scientific era" as being primitive/superstitious/non-methodical/etc. Only later on did we realize that many ancient civilizations were quite advanced in many aspects of mathematics and science though their way of approaching/inventing/recording was quite different from our "modern scientific method" and therefore we need to research them from a different pov and without condescension.
PS: History of Mathematics - https://en.wikipedia.org/wiki/History_of_mathematics
// The power to which I must raise 10 to get 100 is 2.
log10(100) = 2
// The power to which I must raise 10 to get 1000 is 3.
log10(1000) = 3
// The power to which I must raise 3 to get 27 is 3.
log3(27) = 3
Also it makes solving equations much more intuitive:
log3(x) = 4
^ This means; the power to which I must raise 3 to get x is 4. So it follows logically that if I raise 3 to the power of 4, I will get x. This makes it intuitive that this equation can be rewritten as:
x = 3 ^ 4
You don't even need to know the algebraic rule. I felt retarded when I figured this out. This was a rule I had memorized before. It's even dumber and easier to infer than the rule to compute derivatives. I wonder why teachers even bother to teach you all these rules when they could just explain the fundamentals to you.
Given a^x = b we define log_a(b) = x where 'a' is a +ve real number - https://en.wikipedia.org/wiki/Logarithm#Definition
The above wikipedia page also details the properties, applications and generalization of the logarithm concept which are non-trivial.
As i pointed out above, that does not help in intuiting why it is helpful and needed. That is why you need to read the history of logarithms and see how we arrived at the above standard.
Napier actually calculated logarithms of sines for every minute from 0-90degrees to simplify astronomical calculations. The complexity/sizes involved, precision needed etc. can all be seen in this detailed paper walking you through the entire process of table construction; Napier’s ideal construction of the logarithms (pdf) - https://locomat.loria.fr/napier/napier1619construction.pdf
Personally I only remember being briefly exposed to log and ln in school. I don't recall doing any complex algebra with them. So when I started doing algebra with them at university, I had to kind of re-learn from scratch.
I asked Claude about the weird way I was taught logs and it said this, which I found interesting:
There's a broader pattern here that shows up all over maths: notation and procedures get taught as the primary object, with the meaning treated as optional enrichment that "advanced" students might appreciate later. For a lot of people it's backwards — the meaning is the cheap, load-bearing thing, and the procedures are what should be derived from it. Logs are maybe the most egregant case because the gap between "incomprehensible button" and "obvious once stated" is a single plain-English sentence.
I had a weird relationship with Math growing up; I alternated between getting very high grades and terrible grades depending on the teacher. I didn't like all the notations and conventions of Math and the way it was taught, but I enjoyed it conceptually. It had ended badly in high school as I did poorly in advanced Math though I did quite well in all my other subjects so I got into a good Software Engineering degree at a top 50 university for engineering globally anyway.
But early in college, it occurred to me that I didn't understand Math concepts as intuitively as I understood programming concepts so I challenged myself to revisit everything from the beginning including numbers, addition, subtraction, fractions, roots, powers, probabilities, derivatives, integrals, vectors, matrices, calculus...
I had to free myself from thinking of Math as symbols on a piece of paper and think of it as being about actual quantities, transformations and combinations. I needed a completely new way to think about it and visualize every single step. When I was practicing calculus, I would stop at each step and try to visualize the equation. For example, when finding the 3D plane perpendicular to a point on a 3D curve, I would put effort into visualizing what happened to the equations across different dimensions at each step when I found the partial derivatives and combined them to get the 3D plane vectors.
My Math grades at university were quite good. I passed all the Math courses with ease and got several distinctions even.
[0] magworld.pw
Although logarithms are certainly ubiquitous in mathematics, I don't think that the mappings that the article's author identifies as logarithms are appropriately viewed as such.
I can't endorse viewing dimension as a logarithm. It appears superficially logarithm-like because we typically (and somewhat unfortunately) write the direct sum of n copies of a vector space V as V^n rather than nV. Writing nV, we simply get the dimension identity dim(nV) = n dim(V). Writing nV instead of V^n also conveniently frees up V^n for the tensor product of n copies of V, with corresponding dimension identity dim(V^n) = dim(V)^n. So I don't think there's any "multiplicative-to-additive" business going on here at all.
Also, I don't think it's advisable to view the p-adic valuation ord_p as a logarithm, even though it's a homomorphisms from the multiplicative group of the rational or p-adic field into the additive group of the rational field. In fact, in many number theoretic contexts, the ratio log_p/ord_p is of particular interest.
I think a good rule of thumb for viewing a mapping as some kind of logarithm is that it has to have some relation with the Taylor expansion of log(1 + x) around x=0. Being a homomorphism from a multiplicative structure into an additive structure isn't enough to get the logarithm title.
Now assume originally you did not have the feature of inheritance in your programming language so you would just create all the classes you need without orgnizing them into an inheritance-tree. Then you upgraded to a language that doe shave inheritance and you wanted to refactor your program to omit duplicate definitions of methods.
What kind of class-hierarchy would you come up with? There is no single way to do it. Some ways are better than others. There migh be more than one optimal way.
Same goes with generalization general, it is part of the language we create to describe things and there are many different languages we may come up with, some simpler, some more difficult to understand.