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Topic: Re: Mma: 13 is not prime!
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Harald Berndt

Posts: 24
Registered: 12/7/04
Re: Mma: 13 is not prime!
Posted: Aug 16, 1996 3:01 AM
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Felix Holderied wrote:
> Please help me:
> In[]:=
> PrimeQ[13]
> Out[]=
> True
> In[]:=
> PrimeQ[p] /.{p->13}
> Out[]=
> False
> WHY?
> Greetings, Felix

It's all in the evaluation order! Basically, you get the answer for


which is evaluated before the replacement takes place (and has of
course the result False). Try instead

ReleaseHold[ Hold[PrimeQ[p]] /.{p->13} ]

Harald Berndt University of California
Research Specialist Forest Products Laboratory
Phone: 510-215-4224 FAX:510-215-4299

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