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Re: it isn't strange?!

  • To: mathgroup at smc.vnet.net
  • Subject: [mg116144] Re: it isn't strange?!
  • From: Daniel Lichtblau <danl at wolfram.com>
  • Date: Thu, 3 Feb 2011 05:31:09 -0500 (EST)

olfa wrote:
> Hi Mathematica community,
> 
> here is my pb:
> 
>  input:
> Reduce[Max[a, b] == Max[c, d], c, Reals]
> output:
>  (d < Max[a, b] && c == Max[a, b]) || (d == Max[a, b] &&  c <= Max[a,
> b])
> 
> when testing this output with 2 initialisations:
> d = 2  a =  4  b = 3  c = 6  here d < Max[4, 3] but c is not equal to
> Max[4, 3]
> 
> d = 4  a =   4  b = 3  c = 6  here d = Max[4, 3] but c is not <= to
> Max[4, 3]
> 
> where is the pb?!

I see no problem in the results below.

In[27]:= rr = Reduce[Max[a, b] == Max[c, d], c, Reals]
Out[27]= (d < Max[a, b] && c == Max[a, b]) || (d == Max[a, b] &&
    c <= Max[a, b])

In[28]:= rr /. {d -> 2, a -> 4, b -> 3, c -> 6}
Out[28]= False

In[29]:= rr /. {d -> 4, a -> 4, b -> 3, c -> 6}
Out[29]= False

It occurs to me that you gave no serious information about what, 
specifically, you did in "testing". That is to say, no code is shown. So 
it is unlikely anyone will succeed in leading you to the lead.

Daniel Lichtblau
Wolfram Research


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