Re: question related to (-1)^(1/3)

*To*: mathgroup at smc.vnet.net*Subject*: [mg131505] Re: question related to (-1)^(1/3)*From*: Alan <alan.isaac at gmail.com>*Date*: Wed, 14 Aug 2013 02:17:18 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <gnqo3c$c95$1@smc.vnet.net> <go63gv$pnd$1@smc.vnet.net>

Here is slightly different example of needing a domain restriction when using ``RecurrenceTable``: RecurrenceTable[ {xx[v + 1] - xx[v] == -3.0*Power[(xx[v + 1] + xx[v])/2.0, 3.0], xx[0] == 1.0}, xx, {v, 0, 50}] Q1: Is there a nice way in Mathematica 9 to restrict the domain to the reals? Q2: If I use ``Re@Power`` instead of ``Power`` I get the expected output, but I also get a bunch of warnings that "Function::slotn: Slot number 2 ... cannot be filled". What is that about? (I'm not asking for the error documentation, but rather why this change produces that warning -- even if I should be able to get from the former to the latter ...) Thanks, Alan Isaac