The Golden Spruce - John Vaillant

[handslive]

Finished it on Friday.  No other comments.  The first rule of book club is we don't talk about book club. :-)

Comments

[buhrger]

the two definitions are equivalent. the official mathematical machinery is as follows:
we define an equivalence ~ by a ~ b if a-b is a multiple of seven. then the sets of which you speak are the equivalence classes of Z with respect to ~. it's fairly easy to show that each of those equivalence classes has precicsely one representative in the integers 0, 1, 2, 3, 4, 5, 6, and slightly more fiddly, but not too complicated to show that we can get away with just doing our arithmetic on those representatives.