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