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Re: More /.{I->-1} craziness

• To: mathgroup at smc.vnet.net
• Subject: [mg106235] Re: More /.{I->-1} craziness
• From: Vince Virgilio <blueschi at gmail.com>
• Date: Wed, 6 Jan 2010 05:56:50 -0500 (EST)
• References: <200912300915.EAA17299@smc.vnet.net> <hhhmn8$o9t$1@smc.vnet.net>

On Jan 5, 1:43 am, Richard Fateman <fate... at cs.berkeley.edu> wrote:


SNIP

> Are you describing Mathematica here?   It seems to me that it is an
> exception that Head[a+b*I] is Plus, but Head[3+4I] is Complex.

SNIP

Please explain why that is an exception.

'a' and 'b' can be anything, not necessarily numbers. Hence a + b*I
can be anything as well (say, notebookA + notebookB * I). Not so for
3, 4, and 3 + 4*I.

Vince Virgilio