nhaliday + puzzles   63

Best Topology Olympiad ***EVER*** - Affine Mess - Quora
Most people take courses in topology, algebraic topology, knot theory, differential topology and what have you without once doing anything with a finite topological space. There may have been some quirky questions about such spaces early on in a point-set topology course, but most of us come out of these courses thinking that finite topological spaces are either discrete or only useful as an exotic counterexample to some standard separation property. The mere idea of calculating the fundamental group for a 4-point space seems ludicrous.

Only it’s not. This is a genuine question, not a joke, and I find it both hilarious and super educational. DO IT!!
nibble  qra  announcement  math  geometry  topology  puzzles  rec-math  oly  links  math.AT  ground-up  finiteness  math.GN 
october 2017 by nhaliday
The Easiest Way to Memorize the Algorithms of Rubik's Cube: 7 Steps
Learn to solve the Rubik’s cube in no time by taking advantage of your visual memory. You’ve probably been playing with Rubik’s cube and wondering how to solve it. Eventually, you may have succeeded by following an online tutorial. While there are several methods to solve the 3x3 cube, these techniques usually consist of a number of algorithms that look something like this: T R Ti Ri Ti Fi T F.

Some people can memorize such sequences without difficulty. But what about the rest of us who are better at remembering peoples faces rather than their names? The good news is that the algorithms can be converted into easy to memorize graphics so that you don’t need to spend days learning the sequences by heart!
diy  puzzles  visuo  spatial  explanation  howto  math.GR  rec-math  wordlessness 
july 2017 by nhaliday
reference request - The coupon collector's earworm - MathOverflow
I have a playlist with, say, N pieces of music. While using the shuffle option (each such piece is played randomly at each step), I realized that, generally speaking, I have to hear quite a lot of times the same piece before the last one appears. It makes me think of the following question:

At the moment the last non already heard piece is played, what is the max, in average, of number of times the same piece has already been played?

A: e log N + o(log N)
q-n-a  overflow  math  math.CO  tidbits  puzzles  probability  magnitude  oly  nibble  concentration-of-measure  binomial 
january 2017 by nhaliday
pr.probability - Google question: In a country in which people only want boys - MathOverflow
- limits to 1/2 w/ number of families -> ∞
- proportion of girls in one family is biased estimator of proportion in general population (larger families w/ more girls count more)
- interesting comment on Douglas Zare's answer (whether process has stopped or not)
puzzles  math  google  thinking  probability  q-n-a  gotchas  tidbits  math.CO  overflow  nibble  paradox  gender  bias-variance  stochastic-processes 
december 2016 by nhaliday
Low-hanging fruit | West Hunter
Think about it: peptic and duodenal ulcer were fairly common, and so were effective antibiotics, starting in the mid-40s. . Every internist in the world – every surgeon – every GP was accidentally curing ulcers – not just one or twice, but again and again. For decades. Almost none of them noticed it, even though it was happening over and over, right in front of their eyes. Those who did notice were ignored until the mid-80s, when Robin Warren and Barry Marshall finally made the discovery stick. Even then, it took something like 10 years for antibiotic treatment of ulcers to become common, even though it was cheap and effective. Or perhaps because it was cheap and effective.

This illustrates an important point: doctors are lousy scientists, lousy researchers. They’re memorizers, not puzzle solvers. Considering that Western medicine was an ineffective pseudoscience – actually, closer to a malignant pseudoscience – for its first two thousand years, we shouldn’t be surprised. Since we’re looking for low-hanging fruit, this is good news. It means that the great discoveries in medicine are probably not mined out. From our point of view, past incompetence predicts future progress. The worse, the better!
stagnation  science  history  medicine  innovation  technology  west-hunter  low-hanging  meta:medicine  the-world-is-just-atoms  🔬  scitariat  info-dynamics  bounded-cognition  error  chart  econotariat  marginal-rev  being-right  ideas  discovery  the-trenches  s:*  alt-inst  ability-competence  cost-benefit  track-record  problem-solving  puzzles 
november 2016 by nhaliday
Olimpiada Informatyczna
old link seems broken?: http://main.edu.pl/en/archive/oi

Polish Informatics Olympiad, known for very difficult problems
database  problem-solving  puzzles  eastern-europe  oly  usaco-ioi  oly-programming  unit  multi  quixotic 
april 2016 by nhaliday

bundles : academegrowth

related tags

ability-competence  academia  accretion  acm  acmtariat  additive  aesthetics  aggregator  ai  ai-control  algebra  algorithms  alt-inst  AMT  announcement  anthropology  applications  approximation  bare-hands  being-right  better-explained  betting  bias-variance  big-list  binomial  bits  blog  boaz-barak  bounded-cognition  calculation  caltech  career  chapman  chart  clarity  clever-rats  cmu  coloring  community  complexity  composition-decomposition  computational-geometry  concentration-of-measure  concrete  confusion  cool  cost-benefit  course  creative  crypto  curiosity  data-structures  database  deep-learning  definite-planning  design  discovery  discussion  distributed  distribution  divide-and-conquer  diy  DP  dynamic  eastern-europe  econotariat  entropy-like  epistemic  error  essay  estimate  examples  expert  expert-experience  explanation  explore-exploit  exposition  extratricky  extrema  fedja  fermi  fiction  finiteness  forum  frontier  game-theory  games  gedanken  gender  geometry  google  gotchas  gowers  graph-theory  greedy  ground-up  guide  gwern  hierarchy  history  hmm  howto  ideas  idk  impact  info-dynamics  information-theory  innovation  insight  intelligence  interdisciplinary  intricacy  intuition  invariance  israel  jobs  language  latent-variables  lecture-notes  lectures  len:long  len:short  limits  linguistics  links  list  logic  low-hanging  lower-bounds  machine-learning  magnitude  marginal-rev  math  math.AG  math.AT  math.CA  math.CO  math.GN  math.GR  math.MG  mathtariat  measure  medicine  mental-math  meta:medicine  metameta  miri-cfar  mit  money  monotonicity  multi  multiplicative  news  nibble  nitty-gritty  nostalgia  oly  oly-programming  open-problems  openai  operational  optics  optimization  org:bleg  org:data  org:inst  org:rec  organization  orourke  overflow  p:whenever  parable  paradox  parsimony  paying-rent  pdf  people  phase-transition  pinker  planning  play  pls  poast  postrat  prediction  priors-posteriors  probability  problem-solving  profile  programming  proofs  pseudorandomness  puzzles  q-n-a  qra  questions  quixotic  quora  rand-approx  rand-complexity  random  ranking  rationality  ratty  rec-math  reddit  reinforcement  research  research-program  risk  roadmap  robust  ryan-odonnell  s:*  safety  science  scitariat  series  skeleton  skunkworks  social  soft-question  spatial  spock  ssc  stackex  stagnation  startups  stats  stochastic-processes  stream  street-fighting  strings  structure  submodular  sum-of-squares  survey  symmetry  synthesis  tcs  tcstariat  technology  techtariat  tetlock  the-trenches  the-world-is-just-atoms  thinking  threat-modeling  tidbits  time-complexity  toolkit  top-n  topology  track-record  trees  tricki  tricks  trivia  unintended-consequences  uniqueness  unit  usaco-ioi  vague  visual-understanding  visuo  water  west-hunter  wiki  wordlessness  wormholes  yoga  yvain  👳  🔬  🖥 

Copy this bookmark:



description:


tags: