Definition of variable limits

During a fit it may happen that the fit routine is trying to achieve its goal by assigning crazy values to the variables (like negative values to a drift length). It is therefor necessary to set certain limits for the variables. This can be done by: 3 VAR(six-letter_name) < <lower limit> <upper limit> > ; [example: A < 0.5 1.5 >  ;] [example: B < (0.99$\ast$B) (1.01$\ast$B) >  ;]