Now, let's move to the new alphabet
To each expression we assign the Gödel number of the expression. We do this according to the following scheme:
| P | M | 1 | 0 | |
| 10 | 100 | 1000 | 10000 | 100000 |
The mirror of an expression
is the expression
followed
by its Gödel number.
A sentence is an
expression having one of the following four forms (where
is any
number):
,
,
,
.
Naturally,
is true iff
is the Gödel number of a
printable expression,
is true iff
is the Gödel number
of an expression whose mirror is printable, and so on.