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Re: Even numbers

• To: mathgroup at yoda.physics.unc.edu
• Subject: Re: Even numbers
• From: a_rubin at dsg4.dse.beckman.com (arthur rubin)
• Date: Fri, 10 Jul 92 07:46:21 PDT

You (martind at puhep1.princeton.edu) write:

  I'd like to know how to set up that a certain "number" 2*k is even
while 2*k+1 is odd, in such a way that then 

 EvenQ[2*k]=True

 OddQ[2*k+1]=True

 I know that with upvalues it is possible to set up that a single symbol
is even:

 n /:EvenQ[n]=True   

but it does not work with the "expression" 2*k.

----------------------------------------------------------
You have to unprotect EvenQ and OddQ (for downvalues) or Plus and Times
(for upvalues).