FOM: ReplyToPratt

Vaughan R. Pratt pratt at cs.Stanford.EDU
Wed Nov 5 12:06:16 EST 1997

>a Boolean algebra (or in operational terms, ~ *is* complement for those
>propositions of the form ~a, making ~a+~~a=1, and ~a~~a=0, and ~~~a =

Oops, I was asleep at the wheel here.  ~a+~~a and ~a~~a are only 1 and
0 respectively in the ~~ retract of H to a Boolean, not in H itself,
sorry about that.   ~~~ = ~ is fine.


More information about the FOM mailing list