In general, it feels like the alphabet can be partitioned into “sections” where you can use other letters in the same section for additional variables that will play similar roles. Something like:
[a,b,c,d]; [f,g,h]; [i,j,k]; [m,n]; [p,q]; [r,s,t]; [u,v,w]; [x,y,z]
Sometimes these can be combined: [m,n,p,q]; [p,q,r,s,t]; [r,s,t,u,v,w]; [u,v,w,x,y,z]
Yep, and when you run out of letters in a section you use the core letter from the section with a subscript.
In general, it feels like the alphabet can be partitioned into “sections” where you can use other letters in the same section for additional variables that will play similar roles. Something like:
[a,b,c,d]; [f,g,h]; [i,j,k]; [m,n]; [p,q]; [r,s,t]; [u,v,w]; [x,y,z]
Sometimes these can be combined: [m,n,p,q]; [p,q,r,s,t]; [r,s,t,u,v,w]; [u,v,w,x,y,z]
Yep, and when you run out of letters in a section you use the core letter from the section with a subscript.