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Mirrors > Home > ILE Home > Th. List > df-sn | Unicode version |
Description: Define the singleton of a
class. Definition 7.1 of [Quine] p. 48. For
convenience, it is well-defined for proper classes, i.e., those that are
not elements of ![]() |
Ref | Expression |
---|---|
df-sn |
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cA |
. . 3
![]() ![]() | |
2 | 1 | csn 3375 |
. 2
![]() ![]() ![]() ![]() |
3 | vx |
. . . . 5
![]() ![]() | |
4 | 3 | cv 1242 |
. . . 4
![]() ![]() |
5 | 4, 1 | wceq 1243 |
. . 3
![]() ![]() ![]() ![]() |
6 | 5, 3 | cab 2026 |
. 2
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
7 | 2, 6 | wceq 1243 |
1
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
Colors of variables: wff set class |
This definition is referenced by: sneq 3386 elsng 3390 csbsng 3431 rabsn 3437 pw0 3511 iunid 3712 dfiota2 4868 uniabio 4877 dfimafn2 5223 fnsnfv 5232 snec 6167 bdcsn 9990 |
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