Re: [Haskell-cafe] Re: Health effects

2008-10-02 Thread Ketil Malde
Adrian Neumann [EMAIL PROTECTED] writes:

 Does this work with more than two colours? i.e. can I recursively
 subdivide the halves into quarters with another cut?

I don't think so.

In order to divide a group, a line needs to pass through somewhere in
the middle, or more precisely, it must intersect the convex hull of
the group. 

Now group each category together so that their convex hulls don't
overlap.  A solution with two lines and four categories would require
the two lines would need to have four disjoint points of intersection.
Which is too many. :-) 

-k
-- 
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Re: [Haskell-cafe] Re: Health effects

2008-10-02 Thread Ryan Ingram
It seems like if your primitive operation is break bar in two you
need exactly n-1 breaks to get n squares, no matter what choice you
make for where to break along the chocolate grid.  This is a simple
consequence of the fact that each break increases the number of pieces
by one.

If you're allowed to hold multiple pieces in your hand when you do the
break it's different.  Then you need a model of how the hands hold the
chocolate.  I think there is a problem when the breaks get
complicated, as if you have to hold the pieces for too long while
setting up the break, some of the chocolate will melt onto your
fingers.

  -- ryan

On Tue, Sep 30, 2008 at 12:56 AM, apfelmus [EMAIL PROTECTED] wrote:
 Andrew Coppin wrote:
 The other day, I sat down to eat a 2 Kg block of chocolate - one of
 those ones that's divided into lots of little squares. I proceeded to
 recursively subdivide it into smaller and smaller blocks, and then eat
 the individual squares in depth-first order. It was only after getting
 through 16 of the things that I stopped to notice that the whole bar
 just happens to have an exact power of two squares on it.

 And it was some time after *that* when I thought to myself ...woah,
 maybe do too much Haskell? o_O

 Seriously, who recursively subdivides their food? I think I have
 something wrong with me...

 A much more important question is: how many break bar in two
 operations did you perform? Can you do it with less?


 Regards,
 apfelmus

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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Gianfranco Alongi
Are we assuming the bars to have an even distribution of mass along
the whole body?


On Wed, Oct 1, 2008 at 2:10 PM, Achim Schneider [EMAIL PROTECTED] wrote:
 Jon Fairbairn [EMAIL PROTECTED] wrote:

 Adrian Neumann [EMAIL PROTECTED] writes:

  I often wonder how many cuts you need to divide a steak in n
  pieces.  You can obviously get n pieces with (sqrt n) cuts
  by cutting a grid.  But I'm sure some smart mathematician
  thought of a (log n) way.

 Are you allowed to move the pieces between cuts?

 Later you're also going to demand to bend it in N dimensions, aren't
 you?

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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Gianfranco Alongi
Throw the no free lunch-theorem on top of that.

http://en.wikipedia.org/wiki/No_free_lunch_theorem

On Wed, Oct 1, 2008 at 3:33 PM, Dominic Steinitz
[EMAIL PROTECTED] wrote:
 Adrian Neumann aneumann at inf.fu-berlin.de writes:


 I often wonder how many cuts you need to divide a steak in n pieces.
 You can obviously get n pieces with (sqrt n) cuts by cutting a grid.
 But I'm sure some smart mathematician thought of a (log n) way.


 You might try the ham sandwich theorem
 http://en.wikipedia.org/wiki/Ham_sandwich_theorem as an hors d'oeuvre.

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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Anton van Straaten

Achim Schneider wrote:

Jon Fairbairn [EMAIL PROTECTED] wrote:


Adrian Neumann [EMAIL PROTECTED] writes:


I often wonder how many cuts you need to divide a steak in n
pieces.  You can obviously get n pieces with (sqrt n) cuts
by cutting a grid.  But I'm sure some smart mathematician
thought of a (log n) way.

Are you allowed to move the pieces between cuts?


Later you're also going to demand to bend it in N dimensions, aren't
you?


If extra dimensions are needed, perhaps the LHC could be pressed into 
service.  Any Haskell programmers working there?


I'm sure we could settle many of these questions by injecting some 
chocolate particles into the accelerator.  Who among us hasn't wondered 
what chocolate looks like when traveling at relativistic speeds?  Best 
case, we produce an infinitely dense micro-black hole made of chocolate, 
which pretty much takes care of the whole recursive subdividing problem.


Plus, when popped into your mouth, it would evaporate via the tastiest 
Hawking radiation imaginable.


Anton

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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Andrew Coppin

Benjamin L.Russell wrote:

On Tue, 30 Sep 2008 19:54:17 +0200, Adrian Neumann
[EMAIL PROTECTED] wrote:

  
I often wonder how many cuts you need to divide a steak in n pieces.  
You can obviously get n pieces with (sqrt n) cuts by cutting a grid.  
But I'm sure some smart mathematician thought of a (log n) way.



Good thing that the chocolate slab was only 2 kg and of finite length.
Had it been of infinite length, we would need Dedekind cuts to
partition it ;)
  


You know, it's interesting... I posted this in another forum, and people 
just said dude, why would you try to eat a whole 2 Kg of chocolate? 
That's really unhealthy. I post the same thing here and now people are 
arguing about Dedekind cuts... da HELL?! o_O


An interesting dichotomy of perspectives, don't you think?

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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Brandon S. Allbery KF8NH

On 2008 Oct 1, at 15:56, Andrew Coppin wrote:

Benjamin L.Russell wrote:

On Tue, 30 Sep 2008 19:54:17 +0200, Adrian Neumann
[EMAIL PROTECTED] wrote:
I often wonder how many cuts you need to divide a steak in n  
pieces.  You can obviously get n pieces with (sqrt n) cuts by  
cutting a grid.  But I'm sure some smart mathematician thought of  
a (log n) way.


Good thing that the chocolate slab was only 2 kg and of finite  
length.

Had it been of infinite length, we would need Dedekind cuts to
partition it ;)


You know, it's interesting... I posted this in another forum, and  
people just said dude, why would you try to eat a whole 2 Kg of  
chocolate? That's really unhealthy. I post the same thing here and  
now people are arguing about Dedekind cuts... da HELL?! o_O


An interesting dichotomy of perspectives, don't you think?



And if you'd posted on the LOPSA (http://lopsa.org) list it would  
probably be a discussion of which OS is which kind of chocolate.   
So?  :)


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system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon universityKF8NH


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Re: [Haskell-cafe] Re: Health effects

2008-10-01 Thread Bill
On Wed, 2008-10-01 at 20:56 +0100, Andrew Coppin wrote:
   . . .
 You know, it's interesting... I posted this in another forum, and people 
 just said dude, why would you try to eat a whole 2 Kg of chocolate? 
 That's really unhealthy. I post the same thing here and now people are 
 arguing about Dedekind cuts... da HELL?! o_O
 
 An interesting dichotomy of perspectives, don't you think?

Maybe the dichotomy is in the distribution of free-wheeling imagination.
I'm reminded of the (apocryphal?) story about Hilbert's assessment of
poetry and mathematics.

 -- Bill Wood


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