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Home » Olympiad Section » Inequalities » Inequalities Unsolved Problems
 
Problem Searching and Naming!
Moderators: High School Olympiad Moderators, Arne, blahblahblah, Cezar Lupu, darij grinberg, harazi, Megus, N.T.TUAN, orl, pbornsztein, pvthuan
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harazi
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#1
 Problem Searching and Naming!
Ok, guys, then probably it is easier if I delete my stupid posts with easy, hard, nice,... and so there will be fewer posts and people will remember. The problem that I see is that there are too many stupid inequalities, which are only copies of old discussed ones. Strangely, the topic names were not a problem earlier Wink , but suddenly they became. It would be probably easier to distinguish in some way the really useful inequalities from copies. But of course, this is just my opinion...

PostPosted: Sun Dec 19, 2004 12:30 pm  Back to top 
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Myth
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#2
harazi wrote:
Strangely, the topic names were not a problem earlier Wink , but suddenly they became.

It was a big problem for ages.

Quote:
It would be probably easier to distinguish in some way the really useful inequalities from copies.

Hmm... Useful inequalities... Confused Do you mean x^2\geq 0?
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PostPosted: Sun Dec 19, 2004 12:34 pm  Back to top 
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harazi
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#3
Ok, if you prefer solving the same inequality 3 times just because some notations differ, then so be it. Personally, I do not have any problem with that, by I just observe that some problems are so insistently repeated that they became myths.

PostPosted: Sun Dec 19, 2004 12:51 pm  Back to top 
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Myth
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#4
harazi wrote:
Ok, if you prefer solving the same inequality 3 times just because some notations differ, then so be it. Personally, I do not have any problem with that, by I just observe that some problems are so insistently repeated that they became myths.

I agree. But what can we do? What is your solution for that?
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Myth is out of here

PostPosted: Sun Dec 19, 2004 12:54 pm  Back to top 
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harazi
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#5
As far as I have seen, there are just a few hundreds very good inequalities, that are extremely useful and that have very nice ideas. So, we (the moderators and anyone who knows well the content of this subforum) could very well try to qualify very good problems( I know, this will be a difficult job, since it involves lot of subjectivity, but we can easily remark which are the problems which really repeat and are extremely discussed and I really think that we can manage to have an objective selection) and move them in a special area, so that it can be easier to search for them. Of course, this includes changing their topic names, but this is not very difficult since we dont have to do this for all 5000 problems o more which were already discussed. Secondly, I beg the users of the forum to look very well before posting their problems, since it becomes really obsessing to solve 10 times the same problem. Of course, now it is very difficult to find old nice problems, since there are already thousands of problems solved and discussed, but the idea is that between these thousands only a few hundreds are requested each time. I dont know if such a thing can work, but I know that if we dont do something we will have a few hundreds of good problems solved at least 10 times, even if on the site it is written that there are 6000 problems.

PostPosted: Mon Dec 20, 2004 12:07 am  Back to top 
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Myth
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#6
I can definitely say that I don't know contents of this subforum.
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PostPosted: Mon Dec 20, 2004 12:10 am  Back to top 
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harazi
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#7
Yes, Myth, but we need you since you definitely know the level of difficulty of a problem and moreover you know very well which problems are good and useful!

PostPosted: Mon Dec 20, 2004 12:24 am  Back to top 
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Valentin Vornicu
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#8
 
Ok, I've splitted the discussion and made it into an announcement. I agree with Harazi that some order must come into place. Let's discuss all possible solutions and ideas in this thread only ok?
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PostPosted: Mon Dec 20, 2004 12:36 am  Back to top 
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darij grinberg
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#9
Defining notations
One more thing about posting inequalities.

Please don't write up your problems as follows:

A typical geometric inequality wrote:
In a triangle, prove am_a+bm_b+cm_c\leq \sqrt{bc}m_a+\sqrt{ca}m_b+\sqrt{ab}m_c.


Rather try to write them up as follows:

A typical geometric inequality wrote:
Let ABC be a triangle, a, b, c its sidelengths and m_a, m_b, m_c the corresponding medians. Prove am_a+bm_b+cm_c\leq \sqrt{bc}m_a+\sqrt{ca}m_b+\sqrt{ab}m_c.


In other words, please explicitely define all notations used instead of hoping that the reader will be able to guess their meaning. In fact, different people from different countries use very different notations for one and the same thing, and also sometimes denote by one and the same letter different things (for instance, the letter p is sometimes used for the perimeter and sometimes for the semiperimeter of a triangle). Assuming notations to be equal all over the world is nonsense and will only lead to confusion. (Of course, medians are usually denoted by m_a, m_b, m_c, but angle bisectors already cause a Babel tower). But there is also another reason why one should introduce notations. In fact, if one wants to find a special inequality concerning the medians of a triangle on MathLinks, and one uses the "Search" function for that aim, then one gets all the posts where the word "median" is explicitely mentioned - hence, one gets e. g. this post:

A typical geometric inequality wrote:
Let ABC be a triangle, a, b, c its sidelengths and m_a, m_b, m_c the corresponding medians. Prove am_a+bm_b+cm_c\leq \sqrt{bc}m_a+\sqrt{ca}m_b+\sqrt{ab}m_c.


- but one doesn't get this post:

A typical geometric inequality wrote:
In a triangle, prove am_a+bm_b+cm_c\leq \sqrt{bc}m_a+\sqrt{ca}m_b+\sqrt{ab}m_c.


since it doesn't contain the word "median" anywhere.

So, I would ask everyone to define all involved notations verbally in the problems.

Thanks!

PS. About the most important inequalities which are often used and posted 10 times - why not just move them into Inequalities Theorems and Formulas?

Darij
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PostPosted: Mon Dec 20, 2004 2:59 am  Back to top 
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Myth
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#10
Yes, I agree. Moreover, following idea came in my head some hours ago: we can define for each (or for almost each) problem list of its keywords. It is the most widespread method, for example, for scientific papers.

Your opinion?
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Myth is out of here

PostPosted: Mon Dec 20, 2004 5:27 am  Back to top 
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harazi
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#11
Good!

PostPosted: Mon Dec 20, 2004 6:23 am  Back to top 
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billzhao
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#12
A lot of the inequalities can be reflected in the title of the thread (that is, to just use the ineq, or part of it, as the title). Such way of naming topics is a lot more informative than "nice and hard".

I mentioned this quite a number of times now, if the search engine would allow us to display only the first post of each thread (with LaTeX enabled), then finding a particular inequality would be much easier.
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Yufei Zhao

PostPosted: Mon Dec 20, 2004 7:23 am  Back to top 
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Myth
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#13
billzhao wrote:
I mentioned this quite a number of times now, if the search engine would allow us to display only the first post of each thread (with LaTeX enabled), then finding a particular inequality would be much easier.

Of course, if you have unlimited traffic Mr. Green
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PostPosted: Mon Dec 20, 2004 7:25 am  Back to top 
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Valentin Vornicu
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#14
billzhao wrote:
I mentioned this quite a number of times now, if the search engine would allow us to display only the first post of each thread (with LaTeX enabled), then finding a particular inequality would be much easier.
It will be able soon. I will do that, when all the other stuff is bug-free (which is not, some latex stuff is still broken in different places).

I like Myth's idea, however I think it would be hard to apply. It would be indeed easier to move some of the most well-known inequalities, those that come up over and over again to the Theorems and Forumlaes section ..
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PostPosted: Mon Dec 20, 2004 8:44 am  Back to top 
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Megus
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#15
I think Myth idea with keywords is really good. We could add in brackets this keyword for example "[trig] in triangle" - or something like that. With for example 10 of such keywords finding inequality would be MUCH easier. What do you think of it ??
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PostPosted: Mon Dec 20, 2004 10:35 am  Back to top 
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orl
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#16
Megus wrote:
I think Myth idea with keywords is really good. We could add in brackets this keyword for example "[trig] in triangle" - or something like that. With for example 10 of such keywords finding inequality would be MUCH easier. What do you think of it ??


My proposal: Extending this idea to other subjects than inequalities. Smile

As Peter DVD suggested once but slightly changed. Experienced users might be allowed to rank the level of the problems. As these are just a few selected people we will know appropriate difficulty level. We know the skills of these people. Smile
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PostPosted: Mon Dec 20, 2004 1:39 pm  Back to top 
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Valentin Vornicu
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#17
orl wrote:
As Peter DVD suggested once but slightly changed. Experienced users might be allowed to rank the level of the problems. As these are just a few selected people we will know appropriate difficulty level. We know the skills of these people. Smile
Ranking was planned post-wize, but then I had to rush into creating the new board, thus that has moved (once again) further in the future.
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PostPosted: Mon Dec 20, 2004 2:13 pm  Back to top 
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Myth
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#18
orl wrote:
My proposal: Extending this idea to other subjects than inequalities. Smile

Actually, I didn't mean inequalities at all.
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PostPosted: Mon Dec 20, 2004 9:44 pm  Back to top 
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Megus
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#19
So wat about proper naming of topics ? - I see nothing has changed so far, but maybe we could start to change it somehow... still topics named "easy,nice,hard" appears in a great number. Confused
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PostPosted: Thu Dec 23, 2004 11:21 am  Back to top 
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Myth
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#20
Unfortunatelly, users don't hear me... Sad Though I say them from time to time to change titles.
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Myth is out of here

PostPosted: Thu Dec 23, 2004 11:24 am  Back to top 
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