3 ms·
The function n -> n + 1 maps every even number into an odd, and it has an inverse (obviously n -> n - 1). Thus, the two sets have the same cardinality.
by alphabetam 11y ago
The function n -> n + 1 maps every even number into an odd, and it has an inverse (obviously n -> n - 1). Thus, the two sets have the same cardinality.
- bpicolo 11y agoInto a unique odd (which is key) : P