Re: Can't Remove[] variable "K"? (Really strange behavior . . . )

*To*: mathgroup at smc.vnet.net*Subject*: [mg69143] Re: [mg69131] Can't Remove[] variable "K"? (Really strange behavior . . . )*From*: "Carl K. Woll" <carlw at wolfram.com>*Date*: Thu, 31 Aug 2006 04:38:52 -0400 (EDT)*References*: <200608301035.GAA28076@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

AES wrote: > For years I've started every notebook with the input line > > x; Remove["Global`*"]; > > so every calculation will start more or less "fresh". Recently a > calculation exhibited weird behavior involving a variable "K", which > didn't seem to get removed or cleared by Remove[]. I eventually boiled > this down to a simple free-standing 5 Input cell notebook as follows: > > x; Remove["Global`*"]; > K=0.6; > Remove["Global`*"]; > Remove::"rmnsm" > There are no symbols matching "Global`*". Moreï¿½ > K > 0.6 > ??K > K is a default generic name for a summation index in a symbolic > sum. > K = 0.6 > Notice the usage message for K. This is because K is a System symbol: In[2]:= Context[K] Out[2]= System` Carl Woll Wolfram Research > Notes: > > 1) This is on a Mac iBook G4, OS 10.3.9, Mathematica 5.1.0.0. > > 2) Each single-indent line is an Input cell; double-indent lines are > Output cells. Behavior repeats the same after re-typing all the cells > into a fresh notebook; after quitting and re-starting Mathematica; after > shutting down and restarting the Mac. > > 3) I appreciate that user variables preferably start with lower case -- > but other single-cap-letter symbol names work OK, and doing Help on "K" > brings up nothing special associated with K by itself. > > [And by the way, how can one select a sequence of cells in a notebook > and copy all their contents -- including error msgs -- to paste in as > above, without having to retype most of the stuff?)

**References**:**Can't Remove[] variable "K"? (Really strange behavior . . . )***From:*AES <siegman@stanford.edu>