Now there are those that believe that RL-RL is undefined in much the same manner the division by zero is undefined. in actuality it can be expressed in this simples formula.
RL-RL+M>= N
Where M=Modeling & N=Nirvana. Some have aligned themselves with the Utopian school where U may be substituted for N.
Glad to see you back at it Bill. Looks great.