enrich
open-file-handles
with
functions max : open-file-handles → nat;
axioms max-empty : ⊦ max(∅) = 0;
used for: ls;
max-rec : ⊦ max(ofh[fd, fh]) = (fd > max(ofh) ⊃ fd;max(ofh));
used for: ls;
end enrich