452 karma · joined November 21, 2017
But it does so once per day, unless you pay (the low depth analysis you get for free on chess.com is not great to put it mildly)
If you do ask make sure to include approximately when you read it and please let me know, I'm curious about your story too now!
Getting 80% in an exam in a weak cohort of students might earn you an A, while doing so in a strong one might get you a B instead. Is this fair toward a student getting a B this year with the same score that earned somebody an A the year earlier just because they happened to enroll with different peers?
Also why should the grade distribution of an exam be determined beforehand?
Reading posts from former employees and plagiarism accusations (look up Matthew Cook) suggests otherwise.
I remember this being discussed on HN before as well, even though the search function is not bringing up anything.
I draw on paper when I'm trying to visualize something, but the area I work in is quite abstract and very often the images are huge oversimplifications that give some intuition, but on which one shouldn't rely too much.
I agree that the suggested method doesn't sound like a good approach at all to me
Wouldn't German travelers also take advantage of French high speed trains when travelling to Spain?
There is a wikipedia page[1] concerning megalithic architecture in Lazio (the region of Italy in which Rome is), which unfortunately is only available in Italian but contains some information about the estimated age of most of the structures from the linked submission, as well as attempted explanations. For example archeologists suppose that some of the most advanced walls where built by local populations helped by wandering Greek builders based on similarities with the temple of Delphi and Greek acropolises. Wikipedia also has individual pages for some of the ruins[2][3] (also not available in English) where other theories are suggested, for example the acropolis of Alatri could have been built by the Hernici[4].
[1] https://it.m.wikipedia.org/wiki/Architettura_megalitica_del_...
[2] https://it.m.wikipedia.org/wiki/Acropoli_di_Arpino
This is the only sensible way to interpret claims of independency, since if ZFC is inconsistent it just proves every statement so there's no independent ones
The two main techniques to produce new models of ZFC are inner models, that is submodels of a model, for example studying the inner model L (Gödel's constructible universe) is how the consistency of the continuum hypothesis, the generalized continuum hypothesis, the existence of Suslin trees etc. was shown. Looking at L also allows one to conclude that the axiom of choice is consistent with ZF. Another commonly study inner model is the so called HOD, and there's a whole area, "inner model theory" that essentially tries to construct canonical inner models for some statements.
The second big way to produce a model of ZFC is by forcing. This is a very versatile tool that allows to extend a given model of ZFC by adding a new set to it (for example by adding a lot of new reals numbers to a model of CH you can make CH false). Forcing is how the consistency of the negation of CH and GCH was proved.
An interisting example is the negation of AC and its consistency with ZF. If you happen to live in a model of AC every forcing extension will still be a model of AC so it seems that our previous techniques are powerless. But actually what can be done is to look at a carefully chosen submodel of a forcing extension that still models ZF but in which AC fails.
Assume that CH fails and well order the reals. An initial segment of length omega_1 is an example of such a set.
Topology and set theoretic topology is full of those statements, are there Suslin lines? Are there S-spaces? Is the product of two ccc spaces also ccc? The list goes on
Another one from analysis is a very strong form of Fubini's theorem that was shown independent by Friedman.
There's surely more but those are the ones I could remember right now!