Math 346 Lecture 00 - Crash course on logic and proofs, part 2

[greense]

In the various even and odd proofs, where we assert that some expressions in k are equal to an integer, which we label "l", we are using the property of the closure of the set of integers under the operations of multiplication and addition. (Just to close the loop on justifying that assertion.)


I enjoyed this fine lecture. Thanks for posting.

[kyungchanim]

for the part @1:32:00, if we replace n for n+1, why the statement is 1+2+...+n+(n+1) instead of 1+2+...+(n-1)+(n+1)?