Quotient ring work went really well! Scooped up quite a few new properties. And for future rings, assuming we spend a little time inserting it into the lattice of subrings and quotient rings, will get their properties filled out more rapidly.

Several new rings have been added. Among them is the ring of row-and-column finite matrices. Dyunov pointed me to this interesting theorem that every countably-generated F-algebra embeds in RCFM_\omega (F). Even really strange ones. That makes RCFM(F) fairly special!

I had not realized how much interest there used to be (still is?) in End(V) when the dimension of V is infinite