MathGroup Archive 1992

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Re: >=0

  • To: mathgroup at
  • Subject: Re: >=0
  • From: gaylord at
  • Date: Thu, 15 Oct 1992 09:24:18 -0500

a additional note on the question:

you must have made an error because

using the rewrite rule g[x_] := If[x>=0,True,False]

and inputting
g[2 y^2]

If[2 y >= 0, True, False]

it does not return False (you probably got a false  with a rewrite rule you
forgot to clear).

the reason is that since y is undefined mathematica can't decide if it is
true or false and so it returns the input unevaluated.

the rest of my discussion is, i believe, okay.

richard j. gaylord, university of illinois, gaylord at

"if you're not programming functionally, then you must be programming

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