simple question

*To*: mathgroup at smc.vnet.net*Subject*: [mg99649] simple question*From*: Francisco Gutierrez <fgutiers2002 at yahoo.com>*Date*: Sun, 10 May 2009 05:16:16 -0400 (EDT)

Dear Sirs: I have a function whose output is of the form {{a,b,c},{d,e,f},k} That is, a list of length 3, of which the first two parts are lists and the last part is a number Now, I want to iterate it, with the following termination criterion: stop if the first two parts of the output are identical in two successive runs. The intuitive (or naively intuitive if you want) way of attacking the problem, I think, is the following: NestWhile[f,startinglist,UnsameQ[{#[[1]],#[[2]]}&,2] But it does not work. What is the solution? Fg

**Follow-Ups**:**Re: simple question***From:*DrMajorBob <btreat1@austin.rr.com>