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Mathematical Notation Is Awful

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Re: Mathematical Notation Is Awful

#51

I have similar feelings with music notation too. we never applied our "user experience" standards to mathematical notation and music notation. If these things were invented today, we might come up with better ideas. One painful experience I have reading math is telling which variables are "vectors" and which are "scalars". another is the similar looks of certain greek characters and english characters, such as alpha…

I was just going to mention music. I learned some piano as an adult. I was never able to accept that the same note positions on the treble staff had a different value on the bass staff. Yes, I understand why it's so, it's just terribly user-unfriendly.

Also, in keys other than C, I felt that it wouldn't kill them to mark every instance of the sharp and flat notes, instead of doing it once at the beginning and implying it everywhere else.

Re: Mathematical Notation Is Awful

#52
Funny, I said the same about Andrew Ng's ML course.

Ultimately, if what you're teaching is going to end up in software, why use math at all? Use code or pseudo code. I don't think it's bad to just give the working algorithm without having to prove the math.

Really how many students will end up being computer scientists anyway, and research and write about new methods of doing AI, and do the actual math? So few. I guess that's a simple criticism of academics.

It's just easier to work with code than mathematical notation most of the time, in my view. You can't replace math, of course, but when things are simple enough, it could be avoided. It's a matter of making math accessible to the most people.

Code is amazing because a computer can check to see if it works. A computer doesn't understand math.

Re: Mathematical Notation Is Awful

#53

This a thousand times. I boycott math notation. My most memorable math moments are: - giving a talk on notation in high school (I was not tasked to do this, I decided to do it on my own) because I was FREAKED OUT by how we were using tons of symbols nobody had ever explained or defined - converting all Math I encountered in University to Common Lisp programs to get rid of the shit notation - bursting into crazy laugh…

I had the similar experience when I started to learn math, even the Common Lisp part. I knew how to program from young age and I thought math syntactically. From that mindset it was obviously painful.

But once you really start to understand math, you realize that mathematical notation is not very formal or rigorous. It's shorthand visual help to keep track actual mathematical objects behind the notation. S-expressions are perfect for formal definitions and programming. They are not so good for actually thinking mathematics. Mathematical notation can be dense and contain lots of information.

Notation is problematic for students because underlying concepts or notation is almost never explained well. For example, I don't remember anyone explaining what functional or implicit functions are before using them heavily. I had to figure them out myself.

Re: Mathematical Notation Is Awful

#54
post #13

These are just issues that someone unfamiliar with a field would face. None of them are problems for those of us in the field. First, the expectation thing. He's using a special case, E(X), and complaining that the more general case doesn't follow the general case. It's like saying "Well the plural of mouse is mice but the plural of house isn't hice!". The general definition of expectation (for a discrete probability…

In the other words, E(...) has a hidden lambda there, and the fully consistent usage would be E(X -> X^2) (instead of E(X^2)) and so on. The covariance thing would be E((X,Y) -> X*Y) with an implied domain being a Cartesian product of that of X and Y. Of course we humans can easily infer the domains, and writing explicit domains every time is not efficient.

I understood math better once I used it for coding.

Linear algebra and matrices, for example, by creating a simple 3D simulation and later studying a circuit simulation.

Same with physics and other sciences, which are typically taught more like math calculation and/or memorization classes.

It would be nice to see more math documented and taught as code.

Re: Mathematical Notation Is Awful

#55
post #8
post #5

Earlier quoted context omitted.

You should learn what the concepts mean instead of judging the names associated to them. We call something a Ring to avoid saying "a set with two operations which behave in a certain way [...]" every time we refer to it.

"We call something a Ring to avoid saying" Why a "Ring" and not an "asda2+"?

Some people use "rig" to mean "ring wihout negatives" and "rng" to mean "ring without identity".

Re: Mathematical Notation Is Awful

#56
If you think probability theory is bad...

The old joke that "differential geometry is the study of properties that are invariant under change of notation" is funny primarily because it is alarmingly close to the truth. Every geometer has his or her favorite system of notation, and while the systems are all in some sense formally isomorphic, the transformations required to get from one to another are often not at all obvious to the student. —John M. Lee, "Introduction to Smooth Manifolds"

Re: Mathematical Notation Is Awful

#57
This is just really weakly argued. Firstly, the notation does use capital X and and lowercase x. You need to realize these are different. It's not substitution to go from X^2 to x^2. Capital letters are not real numbers, and thus it's a type error too. Secondly, if you are familiar with differentiation and integration, you are familiar with straight substitution not always being correct.

Re: Mathematical Notation Is Awful

#58
post #34

I think the fundamental source of confusion might be due to not understanding the concept of a random variable. In his example, X is a random variable; the expectation E[X] is an functional applied to its probability mass function. Given this, it should not be surprising if it seems to behave differently to "any other function, in math". If you understand this, I think the notation is natural: We have a random variab…

You are right, and the deeper source of the authers beef seems to be that he wants mathematics to be about textual rules. Now that's a fine thing in a computer language -- and there are philosophers who say mathematical truth is no more than computation. But mathematical notation is for humans to talk about things that have meanings that humans can understand. The fact is that E[X^2] is natural way of an important co…

> Now that's a fine thing in a computer language -- and there are philosophers who say mathematical truth is no more than computation. But mathematical notation is for humans to talk about things that have meanings that humans can understand.

Then how come an unfamiliar piece of source code is easier to follow than a mathematics paper using unfamiliar notation?

You can look up the definition of each function and learn precisely what it does, without ambiguities. You can open up a debugger and trace every step of the algorithm. Source code tends to be formatted to emphasise its division into units that can be analysed separately. Even if the code uses a framework you don't recognise, you can probably understand some of the underlying logic just fine, thanks to a consistent syntax and (often) descriptive function names.

In a mathematical paper, often there's some notation that isn't defined and there isn't even any pointer where to look for definitions. Important objects are given one-letter names. Theorems are often only numbered; good luck remembering what lemma 2.17.3b was about. Proofs are written in prose (instead of something like Leslie Lamport proposed[0]). You have to fill in conceptual gaps and remind yourself of unstated assumptions. Notation and terminology is often ambiguous — what does "exponential time" mean? Is it DTIME(2^(c*n)) or DTIME(2^polynomial(n))? Does "increasing" mean "strictly increasing" or "non-decreasing"? Is zero a natural number? And so on.

A mathematical formalism that could be interpreted in a purely mechanical way would be a huge improvement.

[0] http://research.microsoft.com/en-us/um/people/lamport/pubs/p...

Re: Mathematical Notation Is Awful

#59
post #50
post #13

These are just issues that someone unfamiliar with a field would face. None of them are problems for those of us in the field. First, the expectation thing. He's using a special case, E(X), and complaining that the more general case doesn't follow the general case. It's like saying "Well the plural of mouse is mice but the plural of house isn't hice!". The general definition of expectation (for a discrete probability…

I have taken ten years of math in school and then calculus, discrete math, linear algebra. That's all useless if I want to follow math in a simple research paper because they're using notation common in THAT field and it has nothing to do with the notation in another math field. And it's all V hat superscript pi subscript h. It's not like code, where I get descriptive variable names. And you thought pi meant pi? No,…

Reading a "simple" research paper requires a different approach compared to reading a newspaper or a blog. I hope the following explanation helps.

The notation actually helps to keep things simple. I think of it as a kind of metalinguistic programming [1] where a notation is introduced which then makes the important parts easier to understand.

I am not mathematically inclined but I have to read papers containing maths quite a lot of the time. I tend to read them 3 times.

The first time, I tend to skip the equations altogether and just get a feeling for the paper - what is it about, is it useful for me to read?

The second time I have a pen and a highlighter where I actually label the mathematical symbols with arrows and words (using the textual descriptions). I also highlight important sentences. I think of this stage as trying to make the paper as clear as possible for later reading.

In the third stage I am trying to understand the paper as a whole - something it seems you try to do on the first read, I am familiar with the frustration because this is what I used to do.

I quite enjoy reading papers now and I have more respect for the notation.

[1] https://en.wikipedia.org/wiki/Metalinguistic_abstraction

Re: Mathematical Notation Is Awful

#60
I started doing a lot better in calculus when I started using longer notation (e.g. f = x -> x³ instead of f(x) = x³) and making sure that things "type checked". For instance, this tendency to use f(x) to refer to a function, rather than just f, was very confusing to me, because f(x) is an element of the co-domain while f is a function (typically from real to real in my undergrad classes). I had to figure this out by myself because the textbook I was using and the prof all went with the notation that wouldn't type check. When I finally realized that dy/dx should instead be (d/dx)(f), things started being a lot clearer to me: derivation takes a function and returns a function and f is a function so everything checks out.
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