added some index entries
Uncommented the inclusion of main.labels
Logical equivalence between torus and product of circles
6.4.2 isn't using funext, close #640
errata for ec1373a
remark 1+n=n+1 is not judgmental
clarify exercises 5.2 and 5.3, close #639
errata for bd29d77
close #638
errata for 43ea0a8
Insert missing 'e' on lhs invocation of W-elim.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Merge pull request #645 from ezyang/master

Insert missing 'e' on lhs invocation of W-elim.
errata for 0c6f0c8
Mark Errata (auto)
Increment theorem counter after Lemma 6.5.4.

There used to be a numbered equation (6.5.5) in the proof of 6.5.4,
but it was removed by commit 8f54d16.  Incrementing the counter anyway
ensures that if we ever add new theorems or equations at the end of
section 6.5, they will start with 6.5.6, preventing any confusion.
Added solutions to exercises 6.1 and 6.3
Merge remote-tracking branch 'upstream/master'
kristina's torus
Merge pull request #646 from awodey/master

kristina's torus
exercise_solutions really does need to \input{main.labels}