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Topic: Symbolic manipulation with Sqrt[-1] ?
Replies: 31   Last Post: Dec 10, 2009 1:16 PM

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 Mark McClure Posts: 193 Registered: 9/12/07
Re: Symbolic manipulation with Sqrt[-1] ?
Posted: Dec 6, 2009 12:17 PM

On Dec 6, 10:51 am, Richard Fateman <fate...@cs.berkeley.edu> wrote:
> Mark McClure's objection that (x^2)/x  should have a
> subexpression of x^2 in it is, I think not of the same
> relevance.  ... If Mark wants a system that only parses
> expressions, this can be simulated by turning off the
> simplifier. This is usually a dreadful idea.

I never said that "(x^2)/x should have a subexpression of x^2 in it",
nor do I think it. I simply said that all the examples presented here
can be better understood as specific cases of the situation:
(a) User types in expr,
(b) expr is simplified,
(c) substitution is performed.

You have asserted that it would be great if a-I*b /. I->-I would yield
a+I*b and I actually agree. That doesn't make it a bug, as an
examination of the FullForm shows. I would certainly stop short of
calling it a "feature", however.

Mark

Date Subject Author
12/5/09 AES
12/5/09 Richard Fateman
12/5/09 clicliclic@freenet.de
12/5/09 AES
12/6/09 Nasser Abbasi
12/6/09 Nasser Abbasi
12/6/09 Richard Fateman
12/6/09 Mark McClure
12/6/09 Mark McClure
12/6/09 Nasser Abbasi
12/6/09 Richard Fateman
12/6/09 AES
12/6/09 Mark McClure
12/6/09 Richard Fateman
12/7/09 Nasser Abbasi
12/7/09 Richard Fateman
12/7/09 Nasser Abbasi
12/8/09 clicliclic@freenet.de
12/8/09 Jon McLoone
12/9/09 clicliclic@freenet.de
12/10/09 fateman@gmail.com
12/10/09 Dave
12/10/09 fateman@gmail.com
12/9/09 Dave
12/10/09 Dave
12/6/09 Nasser Abbasi
12/6/09 Richard Fateman
12/6/09 Axel Vogt
12/7/09 clicliclic@freenet.de
12/7/09 G. A. Edgar
12/7/09 Axel Vogt
12/7/09 acer