THEN :
and
The usual practice here in contemporary mathematics is to :
We shall therefore :
| Category | Description |
|---|---|
| Category Zero | contains a single element - the natural number [ 1 ] |
| Category I | contains all [ natural numbers ] that are [ prime numbers ] |
| Category II | contains all [ natural numbers ] that are the product of 2 [ prime numbers ] |
| Category III | contains all [ natural numbers ] that are the product of 3 [ prime numbers ] |
| Category IV | contains all [ natural numbers ] that are the product of 4 [ prime numbers ] |
| Category V | contains all [ natural numbers ] that are the product of 5 [ prime numbers ] |
| Category VI | contains all [ natural numbers ] that are the product of 6 [ prime numbers ] |
| Category VII | contains all [ natural numbers ] that are the product of 7 [ prime numbers ] |
| Category VIII | contains all [ natural numbers ] that are the product of 8 [ prime numbers ] |
| Category IX | contains all [ natural numbers ] that are the product of 9 [ prime numbers ] |
| Category X | contains all [ natural numbers ] that are the product of 10 [ prime numbers ] |
| Category XI | contains all [ natural numbers ] that are the product of 11 [ prime numbers ] |
| and so-on-and-so-forth | |