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MathGroup Archive 2000

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Bugs in Abs and Sign !?

  • To: mathgroup at
  • Subject: [mg25674] Bugs in Abs and Sign !?
  • From: Jack Goldberg <jackgold at>
  • Date: Wed, 18 Oct 2000 02:52:40 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

Hi group.


Abs[x^2] /. Abs[u_] -> fnt[u] 


Sign[x^2] /. Sign[u_] -> fnt[u]

In each case I get  fnt[x]^2.  Shouldn't I get  fnt[x^2]? After all,
g[x^2] /. g[u_] -> fnt[u]  returns fnt[x^2] which is what I have been led
to expect from Mathematica.  I am using ver 4.01 on a PowerMac.

These peculiarities are driving me crazy.  This is the fourth "bug" I have
found in just 2 weeks.  Please tell me I'm wrong.

Thanks guys.


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