3 ms·
> In some time past (long before 3000bce), a shepherd paired sheep and pebbles: as the first sheep walked by, he placed down the first pebble; the second sheep
by posterboy 8y ago
> In some time past (long before 3000bce), a shepherd paired sheep and pebbles: as the first sheep walked by, he placed down the first pebble; the second sheep walked by and down went the second pebble. At the end of the day, the number of pebbles placed down equaled the
number of sheep that walked past. Whether sheep and pebbles, or red dots and blue dots, equality of numbers is defined by pairing off.
Good one.
- throwawaymath 8y agoMore concisely: sets of numbers are equivalent if there exists a bijection between them. EDIT: Oh, the sample chapter actually mentions this exact point in a footnote. I guess I can still be clever by saying, "Sets of numbers are equivalent if they're isomorphic." :)