Your comment shows a common misunderstanding of what mathematicians are trying to do. Modern mathematical notation is not obfuscated, it is in fact making the object being described much easier to perceive for humans.
Explaining the equation you see in English words is what every physics book does, however the equation itself represents a concept that is not human. It comes from an alien universe of symmetries and relations and we have spent centuries to arrive at the current way of writing these down in a way which makes them easy to work with.
You can formulate the solution to a quadratic equation as:
The negative linear term, added and subtracted from the square root of the quantity which is the difference between the square of the linear term and the product of four times the constant term and the quadratic term, all divided by twice the quadratic term.
Modern mathematicians write:
x = (-b +- sqrt(b^2 - 4ac)) / 2a
The difference is night and day. You cannot remove the essential complexity from a problem. You can only try to get close to its representation.
While this might not be the OP's point, but for me the main problem are the one-character variable names. Generally computer code that just operates on cryptic one-letter variable names, is considered bad code. Yet equations almost always have one letter variables and the worst part of all, their meaning is almost never explained anywhere
Case in point, what are b, a and c? what is their meaning if I have to measure them, what is the device for measuring them or what quantity do they represent?
The point is that variables are evil and arbitrary. So you give them short names to signal that you could replace them with anything else, what matters is how they appear together. Additionally different subfields of mathematics and physics usually adopt naming conventions.
Took me years before thinking of variables that way and mathematical expressions are constraints over sets, formulas expressing relations of interests that way.
>Case in point, what are b, a and c? what is their _meaning_
The "b, a, and c" in the quadratic equation are abstractions. They are placeholders for any number. That math equation is purposely designed to not have any concrete meaning for a,b,c. Therefore, asking for their meaning does't make any sense.
I'll try an analogy. We can give provide analogous "computer equation" for taking the last four characters of a string:
s2 = Right(s1, 4);
If someone were to ask "what is the _meaning_ of s1?", it would be a nonsensical question. The s1 is a placeholder for any string. The s1 could be a domain name and you want to extract the TLD (".com", ".org", ".edu"). Or the s1 could be a date "mm-dd-yyyy" and you want to extract the "2016" from ""10-31-2016". The s1 could be a placeholder for a thousand unrelated applications.
If you further generalize the "computer equation" to be take the rightmost "x" amount of characters, you'd replace the "4" with "x" like this:
s2 = Right(s1, x);
... it could trigger confusion as to "what does x _mean_? And what measuring device does it come from?"
The "x" is an abstraction/parameter/argument of any number. That number could be 4, or 40000. (You might be tempted to say, "but I know 'x' stands for the number of characters I want from the string!" If so, by analogy you can also say that "c" in the quadratic equation stands for the number that satisfies the equation when you know "x", "a", and "b" ... which just circles back to each 1-character variable not having a concrete "meaning."
The concrete meaning of "a,b,c" in the quadratic equation depends on whether the equation was modeling something in physics, or engineering, or finance.[1][2]
The concrete meaning of "s1" and "x" in the "computer equation" depends on whether you're parsing logs, decomposing dates, verifying credit card numbers, etc.
The analogy above could have been demonstrated with regex such as "(.+)(.{4})" ... which would trigger questions, *"why do programmers use 1-character symbols such as '.' and '+' instead of "anycharacterm_oneormoretimes_consideredasagroup_then_anycharacters_fourtimes_consideredasagroup" ... etc
tldr: computer programmers also deal with weird-looking "equations" but since they are used to them, they have the background knowledge to decipher them.
I see your point with abstract expressions, but the connection I'm failing to make is - if they are completely abstract, then how can the equation be related to the physical world?
In essence, the equation defines the relations between some values - but if any or some of the values can be replaced by real measurements, then surely the relations between real measurements are not interchangeable?
if they are completely abstract, then how can the equation be related to the physical world?
Math equations do not have to be related to anything in the physical world. It's just that humans have found that some patterns in nature seem to match some equations. Why or how math describes the real world is a deep philosophical question![1]
When G.H. Hardy[2] was exploring certain aspects of number theory and properties of prime numbers, it didn't have any relevance to the real world. 100 years later, we now use the math concepts in public key cryptography.
Does Isaac Newton's "F = ma" of "force = mass times acceleration" describe the "reality" of gravity and how planets move in the solar system? Well -- it does -- and it doesn't. It seemed to match reality well enough to find the planet Neptune -- purely by using math. But Newton's math equations didn't seem to match the "reality" of Mercury's orbit.
Then Einstein came up with another set of math equations that matched the "reality" of Mercury's shifting orbit.[3] But now today's physicists notice that Einstein's formulas don't match the "reality" of galaxies rotating faster than the his formulas predict. Today's physicists are trying to come up with another set of math equations to match that reality (or find the elusive "dark matter" so that Einstein's equations remain unchanged.)
(Einstein's equations do not make Newtons's equations obsolete. Newton's math (that doesn't perfectly match reality) is still good enough to guide Apollo rockets to the Moon and back. It's just not good enough to fully describe how Mercury wiggles around the Sun.)
Math is not reality. Math is its own topic that can stand apart from "physics" or "engineering". (Hence, math is the ultimate abstraction.) It's just sometimes convenient for humans to map some mathematics to some realities. It's often helpful for us to do that. Sometimes it backfires. Some Wall Street guys "mapped" math equations to model the financial behavior of mortgages and they turned out to be wrong.
Put another way: If math is used to model the physical world, it is only an approximation for it.
> Math equations do not have to be related to anything in the physical world.
Not to derail this into philosophy, but that position is conjecture. There are people who adopt a position where all mathematical concepts actually derive from physical structures, ie. a kind of mathematical physicalism. These people hold that the reduction of math to the physical may be obscure, like a reduction of economics to physics, but still real.
Though I can't speak for the parent post's author, applying that post's spirit to your example would instead yield, for the quadratic formula:
'The negative linear term, added and subtracted from the square root of the discriminant, all divided by twice the quadratic term'; then before or after this you'd define the discriminant, as it's an illuminating concept in its own right.
I see the target of this wishful thinking a sort-of middle-ground between a formula's derivation/proof and its compact form.
This is rather poetic. There is no difference, mathematical notation is a natural language and initiated mathematicians will read it in sentence form.
Reading is a process of form recognition disconnect from vocalization. On the other hand, language seems to be mostly perceived as vocalisation, because that's the form it's learned from. As anecdotal evidence, tongue is an idiom for language and people have to make an actual effort to read without vocalizatio in order to increase reading-speed.
Note that your literal example does contain a lot more information about context. IE, you even omitted the quadratic equation itself. That shows exactly the problem that I thought the Parent would mean:
I prefer source code in a given language, that's actually compiled and maybe even proven correct, over terse mathematical notation that leaves a lot to context, intuition and shared information. Computability Theory gave rise to Computers, not the other way around.
Nontrivial knots don't exist in 2D, so not really.
Something almost analogous is if you imagine two circles: one smaller and one larger in 2D. Let's say the smaller circle is inside the larger. It's impossible to move the smaller one outside smoothly without intersecting the larger.
In 3D of course this is trivial, just move the smaller circle up away from the 2D plane, then over the larger one and down on the plane again.
To tie it in a bit tighter with OPs article, I would just add that if we could only perceive two dimensions, the inner circle would disappear as we "move the circle up and away from the 2d plane".
It would only reappear to us once we moved it back down into our plane of perception, safely outside of the other circle.
The relevant bit from OPs article that this is analogous to is:
> "What would we see if you watched this happen in real life? Since we can't see anything outside our 3D slice of 4D space, from our perspective the moving (green) loop would disappear, to reappear later in the unknotted position."
The perfect analogy to knots would be planar and nonplanar graphs. It is always possible to draw a graph without intersections in 3D, but in 2D some graphs are impossible to draw without intersections (nonplanar graphs), such as 5-vertices complete graph.
Explaining the equation you see in English words is what every physics book does, however the equation itself represents a concept that is not human. It comes from an alien universe of symmetries and relations and we have spent centuries to arrive at the current way of writing these down in a way which makes them easy to work with.
You can formulate the solution to a quadratic equation as:
The negative linear term, added and subtracted from the square root of the quantity which is the difference between the square of the linear term and the product of four times the constant term and the quadratic term, all divided by twice the quadratic term.
Modern mathematicians write:
x = (-b +- sqrt(b^2 - 4ac)) / 2a
The difference is night and day. You cannot remove the essential complexity from a problem. You can only try to get close to its representation.