[HN Gopher] Difficult math is about recognizing patterns
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       Difficult math is about recognizing patterns
        
       Author : klevertree
       Score  : 26 points
       Date   : 2021-08-09 20:49 UTC (2 hours ago)
        
 (HTM) web link (get21stnight.com)
 (TXT) w3m dump (get21stnight.com)
        
       | wombatmobile wrote:
       | Don't most experts in most domains work the same way -
       | recognising patterns they've seen before?
       | 
       | That's why an expert can charge so much for 1 hour of time. It is
       | more valuable than days or weeks or months of a non-expert's time
       | who doesn't have the library and can't recognise the pattern.
        
         | jstx1 wrote:
         | I mean "recognising patterns" is a such broad term that you can
         | use it to describe pretty much any mental skill.
        
       | resters wrote:
       | A lot of math is taught in a sloppy way, which thwarts the
       | pattern recognition progress in brains trying to learn it.
       | 
       | Programming is significantly easier than math (for something
       | equivalently complex) because of things like syntax checking and
       | compiler/interpreter errors. This speeds up the pattern
       | recognition process in the human brain.
       | 
       | People who are identified as being skilled at math or programming
       | at a relatively early age are usually those who understood it in
       | spite of the teacher/curriculum, so the ability comes as a
       | surprise.
       | 
       | But many such people do not go on to distinguish themselves in
       | either field in any way. There are always things that come easily
       | to one person vs another, but in math and programming, the early
       | birds are typically the only ones whose interest in the subject
       | isn't destroyed by the teaching methods (because the learning
       | happened in spite of them).
        
       | JacobiX wrote:
       | In discrete mathematics (combinatorics) there are definitely some
       | tools and techniques but seemingly every problem is unique, I'm
       | not quite sure that pattern matching is very useful in this
       | subfield of mathematics ?
        
         | Ericson2314 wrote:
         | That's why combinatorics is a bit of black sheep :D
        
         | paulpauper wrote:
         | Combinatorics is just counting but can be so hard finding the
         | shortcuts
        
         | contravariant wrote:
         | Yeah this view that it's all pattern matching isn't too
         | helpful. I find it more helpful to consider mathematics the art
         | of generalization.
         | 
         | Discrete math is frequently about things with very little
         | structure (e.g. graph theory, where you basically just have
         | _any_ binary relation), so inevitably ends up trying to prove
         | things that are _way_ too general. The flipside is that those
         | theorems do tend to crop up everywhere.
        
       | tarxzvf wrote:
       | Everything is pattern matching (or memorization). You can use
       | this approach to half-automate the solution to a known existing
       | class of problems, but how do you come up with anything new? How
       | did Paul Cohen came up with the forcing technique? Who figured
       | out probabilistic proofs as a possible vector of attack?
       | 
       | "Both these properties, predictability and stability, are special
       | to integrable systems... Since classical mechanics has dealt
       | exclusively with integrable systems for so many years, we have
       | been left with wrong ideas about causality. The mathematical
       | truth, coming from non-integrable systems, is that everything is
       | the cause of everything else: to predict what will happen
       | tomorrow, we must take into account everything that is happening
       | today.
       | 
       | Except in very special cases, there is no clear-cut "causality
       | chain," relating successive events, where each one is the (only)
       | cause of the next in line. Integrable systems are such special
       | cases, and they have led to a view of the world as a
       | juxtaposition of causal chains, running parallel to each other
       | with little or no interference."
       | 
       | - Ivar Ekeland
        
       | mkl wrote:
       | Mathematics is the study of patterns, any kind of pattern, in
       | anything. "Difficulty" of maths problems is a kind of measure of
       | how well you know the patterns involved (which is related to how
       | good our notation, terminology, and visualisations for them are).
       | That means research developing brand new maths or applying it to
       | new problems is often difficult, because no one knows the
       | patterns yet, or has good ways of describing them.
        
       | bob1029 wrote:
       | > What's important to recognize is that these same attributes
       | apply across all levels of math.
       | 
       | Functional/Relational programming models are just a trivial layer
       | on top of math. Everything is pattern recognition at the end of
       | the day.
       | 
       | Domain modeling is the logical extension of building standardized
       | "patterns" that can be leveraged for rapidly building &
       | replicating similar ideas.
       | 
       | Using good modeling techniques is the most important thing for
       | managing complex systems. If you aren't sure, you can always
       | start modeling at 6th normal form, then walk it back to 3NF as
       | the various pieces start to make sense together. If you have your
       | domain in 6NF and are using purely functional/relational
       | programming, there are mountains of mathematical guarantees you
       | can make about the correctness of your software. For instance,
       | 6NF gets rid of null. It forces you to deal with the notion of
       | optional facts using 0..1-1 relations and applicable query
       | constraints.
        
         | saeranv wrote:
         | Is there some high-level mathematical way to interpret these
         | normal forms?
         | 
         | I am not familiar with relational databases and just googled
         | database normalization to get a kind of crude idea of what you
         | are saying, but all the examples I find don't seem to give some
         | high-level mathematical interpretation of database
         | normalization. And it seems like there should be one (I could
         | be way off here) based on how you are talking about forms here.
        
           | Ericson2314 wrote:
           | My guess is that stuff is kinda iffy from a math standpoint.
           | Relational databases are good but I've long suspected the
           | theory needs to be overhauled a bit as we've gotten a lot
           | better at connecting CS to math foundations than in the
           | 1970s. (And indeed math foundations is itself getting better
           | from that process.)
        
         | gyam wrote:
         | I want to learn these. How do I start learning good modelling
         | techniques? Are the NFs you're referring to is same as in DB
         | design? If so, how does that translate to general code/system
         | design. Any pointers you can provide for learning material,
         | concepts, or books will be greatly appreciated. Thanks!
        
           | Ericson2314 wrote:
           | The Codd 1971 stuff on Wikipedia looks like a mess, and I
           | think the original is propbably a bit crufty too (though I
           | don't want to disrespect the old masters, SQL was a high
           | water mark of business thinking about computing in many
           | ways).
           | 
           | I would follow the citations of
           | https://ncatlab.org/nlab/show/lens+%28in+computer+science%29
           | instead. Whatever Spivack can say about this stuff I think is
           | going to be much more worth your while.
           | 
           | Looking at https://arxiv.org/pdf/1602.03501.pdf now.
        
       | TrackerFF wrote:
       | Same goes for problems in data structures and algorithms (read:
       | hackerrank / leetcode problems)
       | 
       | Some people will recognize patterns pretty fast, while others
       | must solve literally hundreds of different problems, before
       | becoming comfortable with the concepts.
       | 
       | People always seem amazed and baffled that some candidates can
       | practically walk into white-board interviews unprepared, other
       | than what they learned / did in their DS&A classes in college,
       | and nail the interviews, while others have to basically prep 6-12
       | months before passing the same interview.
        
       | mkl wrote:
       | I like the teaching idea, but I feel like there is a step missing
       | in here:
       | 
       | > When my students encounter a math problem they can't answer, I
       | have them put it in the error log with an explanation of how they
       | did and how they knew how to do it.
       | 
       | If they can't answer it, where does the "how they knew how to do
       | it" come from? Their teacher/tutor?
        
       | csours wrote:
       | Math is about symbol manipulation. Some of those symbols are
       | numbers, and some of the manipulations are arithmetic.
        
         | anyfoo wrote:
         | I'd personally say the symbols and their manipulation are a
         | good _representation_ of what 's going on in math, but math is
         | overall more general. (By the way, arithmetic is about numbers,
         | maybe you meant algebraic.)
         | 
         | Sometimes manipulating symbols towards an answer is great, but
         | sometimes taking a step back, and looking at a problem through
         | a different lens (e.g. at what you are trying to do
         | intuitively) is vastly superior, and the symbol-manipulating,
         | rigorous formalization (and verification) part comes
         | afterwards.
         | 
         | A few examples (out of very many):
         | 
         | * In signal processing (both digital and analog) it can often
         | be much more insightful to play with visualizations of time
         | domain, spectra, and convolution and multiplication thereof.
         | 
         | * Related but more general: Thinking about the complex
         | exponential as spinning in a circle, or tracing out a corkscrew
         | in 3 dimensions, is a way easier method to grasp it than to
         | look at the equations, which for someone getting into it will
         | look like abstract nonsense[1].
         | 
         | * Topology is about "shape" and "deformation" of objects.
         | 
         | * Discrete Structures is about trees, graphs, and so on.
         | 
         | In all of those, you can hit paths where an intuitive
         | understanding may stay out of reach, and symbolic manipulation
         | through e.g. algebra might remain the only way to work with it,
         | but that is often not generally true for the whole field.
         | 
         | [1] Funnily, that's an actual term used by mathematicians, but
         | usually in another field:
         | https://en.wikipedia.org/wiki/Abstract_nonsense
        
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