Re: Re: Radicals simplify

*To*: mathgroup at smc.vnet.net*Subject*: [mg106411] Re: [mg106386] Re: Radicals simplify*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Mon, 11 Jan 2010 18:54:14 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <hic37h$5ef$1@smc.vnet.net> <201001111030.FAA23508@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Mathematica 7 documentation does NOT say that LeafCount is the criterion for determining simplicity, that is, the default value of ComplexityFunction. Rather it says: "The default ComplexityFunction counts the subexpressions and digits of integers." But it does not even say how it combines the counts of the number of subexpressions and digits of integers! On 1/11/2010 5:30 AM, dh wrote: > Hi, > > why do you think x(x^2 y^3)^(1/4) is simpler than (x^6 y^3)^(1/4)? > > Mathematica needs some criterion for this decision. The default criterion is the > > "LeafCount[..]". If that does not suit you, you must define another > > criterion. > > Daniel > > > > francix wrote: > >> Hi, > >> I am using Matematica 7 and need some help with Radicals. > >> > >> If I do > >> Simplify[(x^4 y^3)^(1/4), x>= 0] I correctly have > >> > >> x (y^3)^(1/4) > >> > >> But If I do > >> > >> Simplify[(x^6 y^3)^(1/4), x>= 0] I get > >> > >> (x^6 y^3)^(1/4) and not the correct answer x(x^2 y^3)^(1/4) > >> > >> Thanks in advanced. > >> > >> > >> > >> > >> > >> > >> > > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**Follow-Ups**:**Re: Re: Re: Radicals simplify***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**References**:**Re: Radicals simplify***From:*dh <dh@metrohm.com>