I made a mistake preparing this problem set.  I replaced all occurences of
"Pascheme" with "Pasqual", not noticing that "Pasqual" was also already
mentioned in the problem set and there were supposed to two distinct languages.
I fixed PS8.TEXT to get rid of this bug after we handed out the problem set.
Note that the solutions, however, only refer to Pasqual -- this is probably a
bug, but I'm not going to fix it.