sphaso

Hey all!
It makes perfect sense: if a graph is k-vertex-connected, for every vertex removed I'm removing at least 2 edges, so why wouldn't it be k-edge-connected?
However, what if my graph has 2 vertices and a lonely edge connecting them. The graph would be 2-vertex-connected (I'm assuming the remaining vertex makes a trivially connected graph) but removing the edge would disconnect the graph!
Does the rule only hold when both vertices and edges are greater or equal than k? It would be pretty silly otherwise... right?

I'm self-studying Pinter's "A book of Abstract Algebra" and kinda got stuck around quotient groups. I think I need a bit more intuition about cosets and normal subgroups.
Here's one confusing theorem I cannot quite grasp:
Let G be an abelian group and let H consist of all the elements of G which have finite order. H is then a normal subgroup of G, therefore we may form the quotient group G/H. We will show next that in G/H no element except the neutral element has finite order.

The proof follows, it seems coherent, but I don't really understand how's that possible. If G/H={Ha, Hb, Hc...} there's bound to be a,b in H so that H(ab) will hav

As any other novice in Haskell I've noticed I can write "map" and "filter" in terms of fold. I suspect I could write scan (so unfolds) in terms of folds as well.
I've looked in vain for a proof or a hint generalizing this: could any (higher order?) function be written as a fold (or nested folds)? could you find a counter-example?
Thank you!

I'm a fullstack developer working with a variety of technologies from C# and Javascript to Haskell and Python.
I'm looking for another dev for stress-free problem solving in an area we can discuss.
We would ideally meet for a live session once a week and keep working in our available spare time asynchronously.
Either comment or PM if the idea sounds appealing.

Hello good folks,
I was recently asked to train a colleague who's been with the company for ages, acting as a COBOL programmer. He seems eager to learn and I'm very eager to teach.
The COBOL dept doesn't have any sane coding standard \ methodology. For all I can gather is GOTOs, global variables and copy-paste galore. They started using SQL last year but they seem kinda shaky on what's a foreign key and why they're important.
We had another COBOL programmer who made the transition. He was a very nice guy, worked hard and all, his code had very few bugs but it was basically a long static method.
This guy I'm training will still be split betw

Hello traveller. u/uhDark and I finished the book last week and are now moving on to greener pastures.
Should you find yourself in need of a helping hand feel free to contact me. My understanding of the material was not always 100% but maybe I can help. I've also kept a physical copy of all the solutions we provided to the exercises (of course we didn't do ALL of them). In the first chapters we've also done even-numbered exercises.
We've really digged the book and learned a ton from it. I cannot speak for my partner in math, but I'd hate for this sub to die. I want other people to profit from this book. So really, feel free to raise your hand. If I can help I w

Hi, I'm working through "Mathematical proofs" by Chartrand, Polimeni, and Zhang. In chapter 5 I came across this example:

The equation [; x^5 + 2x - 5 = 0 ;] has a unique real number solution between x=1 and x=2

Proof: Assume, to the contrary, that the equation [; x^5 + 2x − 5 = 0 ;] has two distinct real number solutions a and b between x = 1 and x = 2. We may assume that a < b. Since 1 < a < b < 2, it follows that [; a^5 + 2a − 5 < b^5 + 2b − 5 ;] . On the other hand, [; a^5 + 2a − 5 = 0 ;] and [; b^5 + 2b − 5 = 0 ;] . Thus
[; 0 = a^5 + 2a − 5 < b^5 + 2b − 5 = 0;]

Hello,
I'm very green to ML and I'm looking for a little project to start getting my hands dirty. I've completed the 3 Pluralsight courses on ML using Encog. One of the proposed case studies is TSP using Genetic Algo.
I want to take things a bit further: suppose we have N cities and our Travelling Salesman has D days to visit them all, how would you model this using ML?
I'm wondering if this problem can be thought as a variant of TSP where you have multiple salesmen, except this time it's the same salesman in disguise. However it is, I'm guessing there needs to be a windowing of nodes, as in, e.g. consider from x to y nodes for each day (or salesman)

Heya, I'm a developer with 3+ years experience in full stack web development, ETL, datawarehousing etc. The stack I use is usually C#, Web API 2.0, AngularJS 1.x, SQL Server. I've also built a mobile app with Ionic + PouchDB + CouchDB.
Lately I'm getting more and more interested in functional programming, learning Haskell and applying FP at work using F#.
I'm not a ninja, but I get by. I can volunteer about 1h during the week and more during weekends.
I'm looking for a team \ project to join, preferably using a functional language. Either PM me or reply here.

Hello,
I'm rewriting some projects at work in F# as an exercise. I met one with a LINQ to SQL query which is a bit daunting. Here is the monster:

return (from t in ctx.Tabs
                    join r in ctx.Regions on t.id equals r.fkTab
                    join l in ctx.Links on r.id equals l.fkRegion
                    where roles.Contains(l.role) || roles.Contains("Administrator")
                    group new
                    {
                        t,r,l
                    } by new { t.id, t.label } into tt
                    select new DomainModel.Portal.Tab
                    {
                        Label = tt.Key.

Hi,
I've recently started reading "Learning FSharp: functional data structures and algorithms" and for all intents and purposes let's suppose this is my first F# book.
I've come across the memoization pattern and I cannot really explain to myself why does it work. The shortest example I could find:

 let memoize f =                 

    let cache = Dictionary<_, _>()               

   fun x ->
       if cache.ContainsKey(x) then cache.[x]
       else let res = f x
           cache.[x] <- res
           res                        
                 

Now, being a C# guy, I'm thinking that dictionary is in the scope

Hey good people, lately I'm learning to Jerk and I noticed quite immediately that after about 20 reps (with a single 12kg bell mind you!) the part where my elbow rests (iliac crest) gets sore with a very (but small) visible bruise.
I thought the jerk starts from a rack, so it was correct to assume that the power comes from the legs and it gets to the arm by the hip.
Am I doing something wrong? do I just need to suck it up and keep going?

EDIT: here's the video! https://youtu.be/67Q9uCkJUxc

EDIT2: should anyone still be interested, I think I figured it out. One problem was, as u/OutOfTHeBottomlessPit suggested, that I wasn't using my tor

Heya,
I thought I'd start gathering videos \ books \ whatevs available on the interwebs so that people interested in GS can learn the proper technique. The techniques for GS can be quite different from the more popular RKC \ Pavel KB training and it might be hard for a beginner to understand the difference.
Right now it's just a random collection with little order \ hierarchy. Feel free to suggest additions \ removals! I'm a beginner myself (been training for about 4 months), still cannot Jerk and Snatch with decent technique, so take everything I say with a lot of salt.

Swing

General guidance:

• the movement is rel

Suppose I give you a list of numbers. I want you to return me a list where each element is the element itself plus the sum of the preceding elements (for the first one add 1).

Example input: [0,1,4]
Example output: [1,2,7]

Working through it: I have 0, 0+1 = 1. I have 1, 1 + sum of preceding elements (1) = 2. I have 4, 4 + sum of preceding elements (3) = 7

Functional neurons: fire away!