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Mirrors > Home > ILE Home > Th. List > df-9 | GIF version |
Description: Define the number 9. (Contributed by NM, 27-May-1999.) |
Ref | Expression |
---|---|
df-9 | ⊢ 9 = (8 + 1) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | c9 8973 | . 2 class 9 | |
2 | c8 8972 | . . 3 class 8 | |
3 | c1 7809 | . . 3 class 1 | |
4 | caddc 7811 | . . 3 class + | |
5 | 2, 3, 4 | co 5872 | . 2 class (8 + 1) |
6 | 1, 5 | wceq 1353 | 1 wff 9 = (8 + 1) |
Colors of variables: wff set class |
This definition is referenced by: 9re 9002 9pos 9019 9m1e8 9041 8p1e9 9055 5p4e9 9063 6p3e9 9065 7p2e9 9066 9nn 9083 8lt9 9112 8p2e10 9459 9p9e18 9473 9t9e81 9508 lgsdir2lem5 14304 |
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