| 1 | initial version |
The "free variable" in your example is r6, and the solution is described by giving how both x and y depend on it. It is certainly not the case that the "alphabetically largest" variable can always be chosen as a free variable, as the system [x==x, y==0] shows.
Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.