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Re: What's this Mathematica function called?

• To: mathgroup at christensen.cybernetics.net
• Subject: [mg965] Re: What's this Mathematica function called?
• From: rubin at msu.edu (Paul A. Rubin)
• Date: Thu, 4 May 1995 04:14:19 -0400
• Organization: Michigan State University

In article <3npou7$od2 at news0.cybernetics.net>,
   martind at carleton.edu (D<martind at carleton.edu>M) wrote:
->First let me apologize for what I'm pretty certain is a question that I 
could
->find if only I searched through the big black book long enough.  However, 
I am
->unable to find an answer anywhere in the index, so I'll ask it here.
->
->What is Mathematica function that determines if one expression depends on
->another?  i.e. if this function were called Depends, it would give output
->something like this:
->
->Depends[x + 3, x]
->==> True
->Depends[y, x]
->==> False
->y := x^2
->Depends[y, x]
->==> True
->Depends[f[g[x]], x]
->==> True
->Depends[f[g[y]], x]
->==> True
->Clear[y]; Depends[f[g[y]], x]
->==> False
->
->I seem to remember running across it at some point, but I'm unable to 
find it
->now...
->
->Daniel Martin
->martind at carleton.edu

I think you want FreeQ.

Paul

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* Paul A. Rubin                                  Phone: (517) 432-3509   *
* Department of Management                       Fax:   (517) 432-1111   *
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Mathematicians are like Frenchmen:  whenever you say something to them,
they translate it into their own language, and at once it is something
entirely different.                                    J. W. v. GOETHE