Hi,

The names of the `isubset' procedures in the Index section are
incorrectly listed as isubset=?, isubset<?, etc.  I'd like to fix
this as an erratum.  Patch attached.

Best regards,

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>

"The most important computer is the one that rages in our skulls
and ever seeks that satisfactory external emulator." --Alan J. Perlis